Fixes for NuGet Packager

Packager actually writes the title and iconUrl metadata now.
Modified required metadata properties to match NuGet spec.
Added property to allow custom specification of the location of
NuGet.exe command line tool.
Continued Fixes for NuGet Packager

Added metadata properties releaseNotes, summary, language, and
copyright. Should now support all available metadata specified in the
Nuspec Reference.
VB6: Build only IfModificationExists feature
Merge pull request #14 from dummy3k/upstream

VB6: Build only IfModificationExists feature
Merge pull request #13 from baerbradford/master

Fixes for NuGet Packager
Fix stylecop, fxcop and vs2013.4 unittest ref break. #7
Merge branch 'master' of https://github.com/mikefourie/MSBuildExtensionPack

Conflicts:
	Solutions/Main/Framework/VisualStudio/VB6.cs
	Solutions/Main/Framework/VisualStudio/VBPProject.cs