added Lissajous curve implementation

See merge request aaroles/gmlib-fork!2

Revert "Fix: Some GLSL compilers (Intel) complain about trying to redefine pre-defined variable gl_FragColor"

This reverts commit 57fcd19e.

Fix: Some GLSL compilers (Intel) complain about trying to redefine pre-defined variable gl_FragColor

-- Library
Version bumped to 0.7.0
Modules reduced to the library itself.

-- Build setup
Now supports/depends on vcpkg on windows.
Tests and benchmarks collected.
All custom CMake scripts deprecated.

-- Source code and headers
Internal include directives are now relative.
Generated module header-files deprecated and left behind in pre 0.7 version.
Generated c++ stl style heders deprecated and left behind in pre 0.7 version.
Various related fixes.

Clang compile basic fixes: unused paramter, etc... Turned on clang compile flag -Wno-conditional-uninitialized.

Added unit tests for compilation of all curves except PErbsCurve and PTCurve, which still have bugs. The unit test for PTriangCurve will only work if PBezierTriangle has been fixed

Fixed gmpheart with adding std for abs, sqrt, pow, sin and cos. Fixed bug in gmpbsplinesurf where editing a selector without grid crashed, added a check for selectorgrid if it is shown or not