Upgraded Quickset to be compatible with Moodle 2.5

Hi Bob, 

I'm fairly new to GitHub and Moodle development, so I hope I'm doing this correctly.

-Matt

Here's a list of what I changed:

-----

Updated code to better conform with Moodle coding style
(http://docs.moodle.org/dev/Coding_style)

Updated UI strings to use get_string(), for better l18n support

Removed code for ajax setting, as it is no longer a user setting (it is
now a site setting)

Updated code for setting the number of visible sections:
-Now a select list, instead of a textbox
-Now respects the DB set maximum number of sections (previously
hard-coded)
-Only show the section setting when the course format supports sections
(e.g. Topics, Weeks, but not Social)

Changed HTML and CSS to be more theme friendly.