Revert "Remove test of point sprite support."

This reverts commit aa0c4513757daa85c2902f4cd72e701354688322.
Rename example to glc_quick
Use QStringLiteral instead of QLatin1String
Add lib export informations
Make GLC_State instance static
Point sprite are know valid by default.
Use QOpenGLFunction to avoid compilation issue on windows.
Link examples to GLC_lib version 3
Delete unused files
Fix a bug when selection mode is different of instance mode
Add the possibility to get body from his id
Add the possibility to get a copy of a world selection set
Add the possibiliti to get the list of selectedBodies and
selectedPrimitive
Add the possibility to handle different selection mode (instance, body
or primitive)
Return the selected bodies and primitive count.
remove usage of QStringLiteral
Removed GLC_Char and GLC_Text class
Use QOpenGLContext instead of QGLContext in GLC_SelectionMaterial class