Split DLL and static log4cplus settings from log4cplus_tests.props into own files.
Add Visual Studio project files for static library log4cplus tests.
MSVC: Make log4cplus static library test projects use static .lib.
Revert most of 439414a49a07d7119f0a58b252a853e8e6fc4dab to avoid crashing
during startup when using static library log4cplus.