Fix for building with GCC and CLang
CMake variable descriptions updated
"Building with CMake" article updated
BuildToolkit.cmake cleaned up and renamed
"TestCases" project and all relating variables removed; custom script added for building environment
DrawAppliInit is copied from occt root to CMake binary dir if the file exists
rebuild platform dependent code by cmake cleaned up
Flex & Bison compiler flags added
RelWithDebInfo OCCT libraries are moved to libi folder; the binary is moved to bini one
CMAKE_BUILD_TYPE is set as Release by-default for a single-configuration generator
env.bat in installation folder has default value of CASDEB that equals to the build type of the last installed OCCT libraries
"building with CMake" article updated