This is simpler than having to use --with-java, --with-javac and
--with-javaincl options and, even more importantly, will usually just work by
default.
- New variable to control version of Visual Studio to use on appveyor
- Enable VS2015 (14.0) for C#
- Run full check-test-suite and not just partialcheck-test-suite since
Appveyor performance improvements since using dedicated Hyper-V
instead of Azure.
- Allow 64 bit Python 2.7 to fail on Appveyor as a vector container
slicing bug needs fixing.
Java and Python time out when running just the test-suite.
Compromise for now... run just partialcheck-test-suite, ie
test just invoking SWIG and not C/C++compile and run tests.
