Removed unused TIMED_OUT state

Change-Id: Ifca2ba5fc3e5d032ef4ab6a142b1468cde435efc
Leave the execution_graph as none until compiled

Instead of forcing a compile when accessing the
execution_graph property just leave it as none until
compiling occurs.

It seems awkward to have the side-effect of automatically
compiling occur when a engine property is accessed.

Change-Id: I2760c369bc5926c6293199cb7e500e98d6c3eeb9
Merge "Removed unused TIMED_OUT state"
Merge "Leave the execution_graph as none until compiled"