refactoring installation scripts to use node prompt module, lots of other fixes

fixed #263, fixed #264, fixed #265
fixing 'use_port' to save into config as boolean
interim commit -- enabling default plugins on setup
fix for admin templates
resolved race condition in plugin auto-enabling (not much of a race... I'd
always lose!!)
missing alert-warning class in plugins admin page
fixes to administrator methods
Merge branch 'master' of github.com:designcreateplay/NodeBB
adding upgradeAdmin method to upgrade script -- pending fix to upgradeUsers