msvc: Reorder solution projects and add project filter files

msvc: Reorder solution projects and add project filter files

Since Visual Studio picks the first project as the default startup
project, move the library projects back to the top of the list. This use
to be the order but was changed in commit 9843b689df.

Add the project filter files to help organize the source files within
the Solution Explorer window pane.

Additionally move the getopt source underneath the msvc directory since
it is only used for Visual Studio builds.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>