Shared lib with MSVC

[jrsnen]

uvgRTP got a possibility to build shared version of the library thanks to @db-tech. The building works with MSVC, but there are more steps needed to make it fully usable.

• At least the public functions have to exported in order for them to be usable. (see kvazaar API as an example). Not sure if this works for classes.
• Create instructions for linking Crypto++ if possible. I remember reading that Crypto++ does not recommend shared version, not sure if this is a problem.
• Test and write instructions

This task is not a high priority since static version works well, but I added this for reference (or if someone wants to start working on this). I'm still working on documenting the features from the PR.