Adding cfg options hpx.commandline.aliasing (control command line aliasing) and hpx.commandline.allow_unknown (allow unknown options to be passed through to hpx_main).
Remove --version and --help command line aliases.
Moved command line alias definitions from [hpx.commandline] to [hpx.commandline.aliases].
Added example demonstrating this.
Merge branch 'master' into improve_commandline_handling
Merge pull request #1209 from STEllAR-GROUP/improve_commandline_handling

Improve command line handling