Interface modification.
ShowcodeSnippet -> Snippet

Changed ShowcodeSnippet to Snippet because it can take any type of
content, not just code. Also refactored content sharing so that it is
easier to add new types of content to share.
Removed system uptime clock.
Added HTML as content share option.
Interface modification.
Added a search box in the tracker.
Merge remote-tracking branch 'koil/master'

Conflicts:
	rsc/default.dmf
	src/struct/Channel.dm
	src/struct/ShowcodeSnippet.dm