Keeping minimum dependency on Paket.Core.Dll and using paket.exe instead for operations that modify the solution

[ruhullahshah]

Reference Issue: https://github.com/fsprojects/Paket.VisualStudio/issues/73

Motivation:

• This patch aims at minimizing the dependency of the plugin on Paket.Core.dll and use paket.exe instead for solution modifying operations. Some projects may be using older versions of paket.exe and their paket.lock files may not be compatible with the newer versions which makes it difficult to upgrade the plugin. Also changes to core paket operations trigger a plugin update.

Assumptions:

• .paket\paket.exe or .paket\paket.bootstrapper.exe exists under the SolutionDirectory

Parts that still rely on Paket.Core.dll

• Package search operation still makes use of the DLL because paket find-packages varies across versions. This can be addressed in later patches and dependency from Paket.Core.dll can be completely removed.

[forki]

@ruhullahshah I so love this!!!!!

[matthid]

We should consider only calling "global" restore instead of project specific restore. It will be a lot faster (ignoring the very first call).

[forki]

@matthid something for another PR?

[matthid]

Well calling the process has some performance impact because argument parsing is quite slow... If somebody can verify this is not too slow we can make another PR, otherwise I'd suggest it here.