uniform map in the GraphicsProgram should not be holding pointers

[enginmanap]

Pointers are creating another indirection in the hot path, which is not providing any benefits, so should be eliminated.

[enginmanap]

This is even worse. Since I am using String names to access them, it causes allocations, and it is like 10th highest CPU user in a profile, just to get the names. Material editor should fix this.