Help and usage messages

Specify that the help option causes the program to exit immediately.

Standardize order of options then positional arguments.

Use standard arg parser

Rewrote debom to mirror the new rebom

debom had many options, which were never useful. Output redirection
should simply be handled by the script that calls debom.

Formatting fixes; Help message fixes

Refactored code into multiple 'packages'. One day these may be
independently installable. For now it's just an organization method.

Rewrote main README and added per-package READMEs.

Also: bug fix on whiched and whichvi. They formerly propogated an error
if $EDITOR or $VISUAL were set to a non-existant executable. Also
improved the inline documentation.

Fix typo

Initial commit of cleaned-up dev branch