UI: Add ARB Program Env Parameters to the state tree
* ProgramEnvParameters were not visible before, even though the snapshot correctly had them.
* ProgramEnvParameters are correctly diff'ed and the previous values are visible in tooltip.
* ProgramEnv 'current program' values were diff'ed before, but the previous value did not appear in the tooltip, this is now fixed.
Merge branch 'master' of https://github.com/ValveSoftware/vogl