Solves mismatch between push_wmops() and pop_wmops()
- fix mismatch between push_wmops() and pop_wmops()
- avoid doubled initialization of structures to NULL
- assign 'hRenderConfig' to NULL in ivas_initialize_handles_dec() -> this fixes a crash in case of premature exit due to unassigned 'hRenderConfig'
- editorial changes
Related to #97 (closed)