*First step to move Part rendering using VBO instead of direct rendering
*Update comments inside the code
*Assume VBO is available if OpenGL > 3.0 is detected
*Add initial Color support to VBO rendering !
*Initial full feature VBO rendering implementation
*Modify some include issue for linux build
*Try to fix linux include header
*Reupdate header include for linux support
*Fix compilation on linux
*Fix linux and MacoOS build
*Fix glGetString definition
*Fix Windows build
*Add VBO support as an option into the Preference menu
*Fix crash while running FreeCAD test bench with new VBO rendering infrastructure (in both cases)
*Improve performances
*Compute material index only when a VBO update is required (improve frame rate by 10%)
*Clean the code
*Fix Travis compilation warning
*Try to fix Windows compilation issue
*Update include for Windows
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It stores a rational BSpline even if non-rational.
It should be extended to store in addition whether it is periodic or not, i.e. to support periodic BSplines.
==============================================================
1) Basic set/get interface for poles, weights, knots and multiplicities
2) Introduction of GeomBoundedCurve class replicating OCC hierarchy. Why? To provide seamless start/end point interface for any bounded curve, i.e. Bezier, BSpline,
Note: The ArcOfConic start/end point interface relies on GeomTrimmedCurve, and introduces CCW/CW correcting code which relies on Axis. Axis are introduced in GeomConic and are
not part of GeomBounded.
Note 2: In the future, it may be thought to make GeomArcOfConic (the equivalent of GeomTrimmedCurve) deriving from GeomBoundedCurve, as to fully replicate OCC hierarchy. GeomBoundedCurve
defines the functions as virtual to allow seamless integration.
Unlike Part.__sortEdges__ which only return a list of connected edges,
and discard the rest. Part.sortEdges return a list of list of
connected edges, which includes all input edges.
