* Removed superfluous configurations
* Removed superfluous include directories and hard-coded library locations
* There are now only 3 configurations: Debug, Playtest and Release
* Debug and Playtest have the PLAYTEST and BALANCE_ENABLED preprocessor commands, while release doesn't
* Release has maximum optimisations enabled. Debug has none, and playtest has minimal
* Removed hard-coded output directories based on half-life installations, dlls are output in the solution folder (and user can customise as they see fit)
* All projects for all configurations compile without warnings or errors
* handle particles project VC++ compilation errors with MVCS and project property changes
- retarget to v142 platformtoolset
- remove explicit windows SDK version; use latest by default
- remove settings that are otherwise default values in project or are best determined by solution
* attempt to handle clang++ issues regarding unsupported c++11 features
* reset file changes to particledefs.h
* removing PARTICLEDLL_API definition and replacing usage with extern "C" block statements
* add g++ compiler option to specify c++11 standard
* attempt to resolve forward enum errors by adding std to base cflags
* replacing deprecated libstdc++ and removing -lstdc++ flag, updating MacOSX10 sdk version
* small refactor to Makefiles, and add libstdc++ back to linux build
* remove added type to enum
* reset makefile changes that may be causing unexpected linux build failures
* refactoring std=c++11 declarations in Makefile to mitgate linux build failing
* ensure std is set for hl_cdll make
* attempt to define a standard library to resolve vector initialization_list constructor issue
* attempt to update MacOS sdk, set minimum os to be 10.7, and include export in travis ci to define deployment target
