General build cleanup

Consolidate buildupdate.sh, /build/buildupdate.mono.sh, and /build/buildupdate.win.sh => /build/buildupdate.sh
Combine Palaso.sln and Palaso VS2010.sln => Palaso.sln (VS2010 and VS2013 compatible)
Remove unused files: PalasoError, Palaso.sln, .hgignore
Since exiftool.exe is replaced with taglib-sharp, remove exiftool from build configuration
Fix SIL.ScriptureUtils.Tests reference to nunit.framework.dll
Did you generate this code or is this hand-written?

The idea of these files is that they get generated by https://github.com/chrisvire/BuildUpdate from the dependencies on TC, so they shouldn't include any hand-crafted code. 

At least in the past we had to have two separate files for Windows and Linux because of the differing dependencies which the BuildUpdate tool wasn't able to merge into a combined file.