Use special syntax for runtime arguments

[melsman]

Currently, executables generated by MLKit takes command-line arguments -h, -help, etc., that control the runtime behaviour of the program. We should use special syntax for these arguments. The proposal here is to follow the technique used by MLton - see http://mlton.org/RunTimeOptions.

Special MLKit runtime options may be given as follows:

./run @MLKit -h -help -- a b c

MLKit will read the options between @MLkit and the first occurrence of --. The following arguments will be available for CommandLine.args(). Which runtime flags are available depends on the runtime system used. When GC is enabled, -disable_gc, -verbose_gc, -report_gc, and -heap_to_live_ratio N are available, for instance.