new RTS flag: -V to modify the resolution of the RTS timer
Fixed version of an old patch by Simon Marlow. His description read: Also, now an arbitrarily short context switch interval may now be specified, as we increase the RTS ticker's resolution to match the requested context switch interval. This also applies to +RTS -i (heap profiling) and +RTS -I (the idle GC timer). +RTS -V is actually only required for increasing the resolution of the profile timer.