Major refactoring of how WindowChrome is used

[batzen]

As the problems regarding our usage of WindowChrome and the bugs WindowChrome contains, we have to rewrite large parts of the codebase which interact or try to workaround bugs in WindowChrome.

I already spoke to the maintainer of MahApp.Metro and we will try to find a solution which enables us to share those fixes, thus only having to fix them once.

This should fix #10, #90, #129 and #180.
#80 should be tested for regression.