Adding highlighting words

Added highlighting words:
Users may now use the new highlight commands:
-Use /highlight add, word to add a highlighting word.
You might add several words separated with commands.
-In a likewise fashion, /highlight delete, word deletes words.
-Using /highlight delete with no words will delete all.
-/highlight show or list will show all current highlight words.
-By default no word is added to highlights.
-Words are escaped
Disable web access to backup directory

This directory should probably just be deleted entirely, but for
now I am just disabling web access to it.
Add ! and # users to the sort order

Users whose names are prefaced by ! (mute) or # (namelock) were
not included in the rank sort order, causing unusual sort results.
Merge pull request #5 from Joimer/patch-1

Adding highlighting words
Nicer highlight color
Feedback for highlight commands
Fix many messages.
Add highlight notification
Don't throw from getHighlight
Revert consolidation of getName and getLowerName
Add `rows` attribute to teambuilder <textarea>s

Firefox renders the height of a <textarea> based on the `rows`
attribute, which was not previously specified, causing the <textarea>
in the teambuilder to be very short. This commit specifies a
(somewhat arbitrary) `rows` attribute so that the <textarea> has
some more height.
Include name rules on rename overlay

The name rules have been copied from http://www.pokemonshowdown.com/rules
Only show username rules while forcerenaming
Add support for permanent `nameTaken` error
Each server now gets its own session

This commit implements the following:

- each server now has a separate session with a 'sid' cookie
  scoped to /~~server:port

- 'sid' cookies are now HTTP-only and not accessible in JavaScript

- the showdown_token cookie is removed

Together, these changes fix various XSS attacks.
Update link in URI
Fix link in README.md
Really fix link
Add notification for new PM
Corretly z-index pokemon in doubles