Retabbed to 4 spaces
Switched to Unix Line Endings
Now builds 'all' by default, allows other rules

if 1 command-line argument, build the rule with that name
if 0, build 'all',
if anything else, print usage.
Bugfix: clear commands array for each new command

Commands previously only appended new words into the array of commands
to run. It should be cleaned between different commands