REMOVED: core_basic_window.cpp

1) use the latest windows SDK not a specific one.
2) use the project dir as the root for the include dir for raylib, to help if the project is ever included in some other solution.

Most warning were related to types conversion (casting required) and unsigned/signed types comparisons.

Added preprocessor directives (_CRT_SECURE_NO_DEPRECATE; _CRT_NONSTDC_NO_DEPRECATE) to avoid warnings about unsafe functions, those functions are safe while used properly and recommended alternatives are MS only.

Some external libraries still generate warnings.

NOTE: When building for 64bit in raylib static mode, CloseWindow() symbol collides with user32.lib symbol. No solution for that at the moment, just compile raylib as shared library (raylib.dll), actually it can be chosen on project configurations.