Added commands remove:src and remove:dist

Added commands for removing "source" and "dist" entries from a composer.lock file.
These commands have a option to "--except" urls with given patterns.

Added check:src command and --allow-empty flag.

Merge pull request #3 from silpion/feature/check_source

Added check:src command. Added --allow-empty flags.

Autoloading fix.

v0.1.1

Updated composer handling.

First useable release.

More ideas for checks welcome :)