- Added support for current default toolset, explitly specified c++17 standard and 8.1 win sdk.
- properties were defined via `common_default.props` and `common_default_macros.props`
Note: There are 2 files because some properties need to be imported before `Microsoft.Cpp.Default.props` , but other common properties can be imported after but they require marco defined in `Microsoft.Cpp.Default.props`.
- Added hidapi and libusb project files to repository to simplify msbuild changes.
Moves GL, minidx12, OpenAL, stblib to 3rdparty
Fixes AppVeyor and CMakeLists (travis-ci.yml doesn't need any changes)
Points directories in the VS solution files to the new ones on the
externals directory
Includes stuff with the < > syntax instead of " "
