Resolve nuget package bug (Extensions is not included for .NET3.5)
Added InputArray constructors from double/Scalar
Merge branch 'SparseMat' of https://github.com/shimat/opencvsharp into SparseMat

Conflicts:
	src/OpenCvSharp.CPlusPlus/OpenCvSharpExtern.dll

Added SparseMat (incomplete)
Added SparseMat methods except accessors
Added SparseMat accessor methods
Merge branch 'SparseMat'