Add FFmpeg.AutoGen as submodule under ThirdParty

So far, CUETools was looking for FFmpeg.AutoGen in a directory
at the same level as the cuetools.net directory. Simplify getting the
sources of FFmpeg.AutoGen by adding it as a submodule.

- Add FFmpeg.AutoGen as a submodule inside the ThirdParty subdir using:
    git submodule add https://github.com/Ruslan-B/FFmpeg.AutoGen.git \
    ThirdParty/FFmpeg.AutoGen
- Checkout the latest release 4.1.0.4 of FFmpeg.AutoGen,
    at commit: 9bb7daad329a103e1c563f80e1d9d7b5715ccff0
    cd ThirdParty/FFmpeg.AutoGen/
    git checkout 4.1.0.4
- Update the path to FFmpeg.AutoGen accordingly in:
  CUETools\CUETools.sln
  CUETools.Codecs.ffmpeg\CUETools.Codecs.ffmpeg.csproj
- Update README.md and remove text about separately getting
  sources of FFmpeg.AutoGen from GitHub
- Add FFmpeg.AutoGen to License.txt

.gitmodules

@@ -16,3 +16,6 @@
 [submodule "ThirdParty/WindowsMediaLib"]
 	path = ThirdParty/WindowsMediaLib
 	url = https://github.com/gchudov/WindowsMediaLib.git
+[submodule "ThirdParty/FFmpeg.AutoGen"]
+	path = ThirdParty/FFmpeg.AutoGen
+	url = https://github.com/Ruslan-B/FFmpeg.AutoGen.git

CUETools.Codecs.ffmpeg/CUETools.Codecs.ffmpeg.csproj

@@ -24,7 +24,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\CUETools.Codecs\CUETools.Codecs.csproj" />
-    <ProjectReference Include="..\..\FFmpeg.AutoGen\FFmpeg.AutoGen\FFmpeg.AutoGen.csproj" />
+    <ProjectReference Include="..\ThirdParty\FFmpeg.AutoGen\FFmpeg.AutoGen\FFmpeg.AutoGen.csproj" />
   </ItemGroup>
 
 </Project>

CUETools/CUETools.sln

@@ -197,7 +197,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CUETools.Codecs.MACLib", ".
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CUETools.Codecs.ffmpeg", "..\CUETools.Codecs.ffmpeg\CUETools.Codecs.ffmpeg.csproj", "{A2C09014-C430-4E58-A323-306CCDF313C5}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "FFmpeg.AutoGen", "..\..\FFmpeg.AutoGen\FFmpeg.AutoGen\FFmpeg.AutoGen.csproj", "{B0A0C17A-C1BC-4CB1-BE1E-F545F54A7923}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "FFmpeg.AutoGen", "..\ThirdParty\FFmpeg.AutoGen\FFmpeg.AutoGen\FFmpeg.AutoGen.csproj", "{B0A0C17A-C1BC-4CB1-BE1E-F545F54A7923}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CUETools.ChaptersToCue", "..\CUETools.ChaptersToCue\CUETools.ChaptersToCue.csproj", "{6ADBBF4B-AD3A-4782-A694-18662196780B}"
 EndProject

CUETools/License.txt

@@ -206,3 +206,24 @@ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ********************************************************************************
+
+********************************************************************************
+                              FFmpeg.AutoGen:
+--------------------------------------------------------------------------------
+                   Copyright (c) Ruslan Balanukhin 2019
+                           All rights reserved.
+
+Distributed under the GNU Lesser General Public License (LGPL) version 3.
+http://www.gnu.org/licenses/lgpl.html
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+********************************************************************************

README.md

@@ -11,10 +11,8 @@ Prebuilt binaries can be downloaded from [CUETools Download](http://cue.tools/wi
 `git clone https://github.com/gchudov/cuetools.net.git`
 * Get the required submodules using:  
 `git submodule update --init --recursive`
-* Get the FFmpeg.AutoGen sources from GitHub ([https://github.com/Ruslan-B/FFmpeg.AutoGen](https://github.com/Ruslan-B/FFmpeg.AutoGen)):  
-`git clone https://github.com/Ruslan-B/FFmpeg.AutoGen.git`
 * The solution can be built using Microsoft Visual Studio 2017 or newer (Community Edition will work)
-  * Install the required .NET framework development tools (currently 4.7)
+  * Install the required .NET development tools (currently .NET Framework 4.7 and .NET Core 2.0)
   * Install an appropriate Windows SDK version (currently 10.0.16299.0)
   * Install the Microsoft Visual Studio Installer Projects
 * Optional: Install [NASM](https://www.nasm.us/) and add it to your PATH. This is required for building the 32-bit flac plugin.