Minor additions and project file updates.

[Gitii]

Hi,

I have some changes (merely improvements), that I would like to share to the public:

• Updated to net 4.5.2 (from 4.5, which is not supported anymore: https://blogs.msdn.microsoft.com/dotnet/2015/12/09/support-ending-for-the-net-framework-4-4-5-and-4-5-1/). The build configurations stayed the same.
• Added ImportFileFromMemory which accepts a pointer (IntPtr) instead of a stream (avoides memory copies).
• Updated outdated mono.cecil with latest (beta) version from nuget & added workaround for related open-file-issue. That is needed due to updated pdb-files of newer c# compilers.
• Updated project files to vs2017 (I only have this one).

I have also extended the unit tests and documented the new function. Greetings,

Gitii

[kimkulling]

Merged, thanks a lot for the contribution.