Set IFS explicitly.

IFS is changed in  sstephenson/rbenv@baf7656
add .ruby-gemset to be gemset file for rbenv
Added completion support to subcommands
Fix version command
Fix version command bug (dying and not showing any output) introduced by the last commit. Thanks @radford (#45)!
update github links to new repo location
Merge pull request #45 from radford/fix-version (thanks, @radford, for your patience, and for sticking with me!)

Fix version command
Improve README: add a TOC!, add History
Update 'version' info
Improve README: 'Usage'
Fix #32
Add support for project gemsets!
Improve README, bump to v0.4.0
Tweak README
Tweak README
get rid of double "shopt nullglob"!
Fix #48; bump version up to 0.4.1
Tweak README: line spacing!
Improve README: add special note and section about environment variables in Usage section!
Tweak README