glDeleteTextures deletes n textures named by the elements of the array textures.
After a texture is deleted, it has no contents or dimensionality,
and its name is free for reuse (for example by glGenTextures).
If a texture that is currently bound is deleted, the binding reverts
to 0 (the default texture).
glDeleteTextures silently ignores 0's and names that do not correspond to
existing textures.
NOTES
glDeleteTextures is available only if the GL version is 1.1 or greater.
ERRORS
GL_INVALID_VALUE is generated if n is negative.
GL_INVALID_OPERATION is generated if glDeleteTextures is executed
between the execution of glBegin and the corresponding
execution of glEnd.
