Add parsing errors on the command line

[isanae]

This works:

.\mob -d C:\MO2-dev\build build --ini ..\another.ini

but this doesn't:

.\mob -d C:\MO2-dev\build build --ini ..\another.ini modorganizer

because once modorganizer is added, --ini becomes part of the build command instead of the global options. clipp doesn't seem to have anything good for reporting errors (this is actually parsed fine, but modorganizer is considered "blocked", whatever that means).

Figure out better error reporting instead of just dumping a useless usage.