Instead of using a different function pointer table for ES 1.x and ES 2.x,
we use a single one that is the union (sort|uniq) of both tables. Two
instances of this table are initialized with pointers to GL ES 1.x and GL ES 2.x
entry-points.
When a context is created, we store its version number and when it is bound to a
thread we set the approruiate table based on the stored version.
This introduce no penalty while dispatching gl calls to the right API version.
[Pending Dr No approval for MR1]
