Prepare for CUETools 2.1.8

- Substitute occurrences of "2.1.7" with "2.1.8" using:
  git grep -I -l -e '2\.1\.7' -- ':(exclude)*.bat' | xargs \
  sed -b -i -e 's/2\.1\.7/2\.1\.8/g'
- Update some outdated version entries:
  2.1.4 in CUETools.CTDB.EACPlugin.Installer.vdproj
    git grep -I -l -e '2\.1\.4' | xargs \
    sed -b -i -e 's/2\.1\.4/2\.1\.8/g'
  2.0.7 in
    CUEPlayer/Properties/DataSources/Output.datasource
    CUEPlayer/Properties/DataSources/frmCUEPlayer.datasource
    git grep -I -l -e '2\.0\.7' | xargs \
    sed -b -i -e 's/2\.0\.7/2\.1\.8/g'
  1.9.4 in CUETools.Processor.CUEConfig.datasource
    git grep -I -l -e '1\.9\.4' | xargs \
    sed -b -i -e 's/1\.9\.4/2\.1\.8/g'
  1.9.0 in frmCUERipper.datasource
    git grep -I -l -e '1\.9\.0' | xargs \
    sed -b -i -e 's/1\.9\.0/2\.1\.8/g'

CUETools.Codecs/CUETools.Codecs.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>net20;net47;netstandard2.0</TargetFrameworks>
-    <Version>2.1.7.0</Version>
+    <Version>2.1.8.0</Version>
     <AssemblyName>CUETools.Codecs</AssemblyName>
     <RootNamespace>CUETools.Codecs</RootNamespace>
     <Product>CUETools</Product>