Add a notice to PHPUnit saying it'll take a while

There is no -v or --verbose option to show a progress bar or similar to avoid people thinking installation is hanging. PHPUnit does take a while to install.
Remove double space from module list
grunt + grunt-watch robustness changes

On bootstrap run grunt default --force to stop error messages
terminating the bootstrap
grunt-watch install runs from the same working directory so the
execution works correctly
Add SASS
Cleaning up scripts

node leaves some files around, so remove them after completion
php-apc can be sped up
UPDATE Moving to CentOS 6.5 box

Using puppet labs 6.5 box now. By default using the clean version (nocm)
rather than one with puppet installed
UPDATE New OS info in README

Adding other OS's that should work with the install scripts
UPDATE _ss_environment.php

Updating the file -> url map as per
http://doc.silverstripe.org/framework/en/topics/environment-management#an-example

adding comments for clarity