Change mode from 1, 2, 3 to upload, download, verify_upload
Simplify --help option

OptionParser implements --help automatically
Replace puts ... exit with abort

abort is equivalent to puts msg; exit 1
Group AUTHMODE with other constants
Rename module so it doesn't look like a constant
Remove duplicate require
Shorten abort statements
Output warnings in addition to help when required args are missing
Merge pull request #2 from ryangreenberg/cleanup_operations

Support named modes