implemented URL handler

triggered by eg. munki://category-all.html
simplified url strip

saving some cpu cycles
added support for hrefs with white spaces

eg. <a href="munki://detail-Adobe CS6 Design Web Premium.html">CS6</a>
corrected URL identifier

now uses standard reverse DNS notation
Reorganization in preparation for implementation of client customization pieces
Fix a few issues caused by the recent code reorganization. Also -- catch HTML parsing errors when filtering description HTML. Fixes issue 307.
Move MSUHTMLFilter from msulib.py to MunkiItems.py
Add additional paths to com.googlecode.munki.MunkiStatus's KeepAlive PathState array. Fixes issue 305.
Non-displayable content URLs are now forwarded to the user's default browser.
Add support for target='_blank' for showcase images so clicking on a showcase slide opens a link in the default browser.
Move JavaScript that runs the showcase slideshow into the showcase_template.html
Fix sidebar display issue on Categories page
Properly deactivate bookmark/controls/buttons if displaying an external page
Improved method of deriving effective updates in getEffectiveUpdateList()
Trigger an updatecheck when adding or removing staged items from the update list
Show a progress spinner over the Updates button when an update (check or install) is in progress
Fix CSS so action button for unavailable item in My Items view is disabled
fixed start to panel from and external URL

prevents initial view to override the call from the handler
Merge branch 'Munki2' of /Users/nbalonso/GitHub/nbalonso's munki2 into Munki2
Use urlparse to parse incoming url, and urllib.unquote to unquote special characters. Don't require an html extension for incoming URLs.