So the "is_src" argument to shader_dump_arr_entry() is redundant (and wrong).

It's used to determine if the token is a source or destination parameter. A
subsequent patch will split shader_dump_param() in two different functions.

Instead of the usage token.

fglrx refuses to use PBOs on not mipmap complete textures. The texture code
already takes care of this, do the same in the test.

Nvidia doesn't offer it on geforce 7 and earlier cards, but some games need
it. This is surprising because the extension was made specifically for
compatibility purposes for older cards.

Checking for the doublebuffer flag can cause confusion if no VBO has
been allocated for the buffer. Checking for allocatedMemory is the
more direct approach.

This fixes a regression in EverQuest 2.