Merge pull request #2 from sagnew/master

Merged in 
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
Give nice messages on invalid JSON
Renamed executable to not have .py
Merge branch 'master' of https://github.com/JarekSed/JSONMake

Conflicts:
	JSONMake.py
	JSONMaker.py
Adding Jarek's changes