Speeding up zone painting.
This merges the scope and instance drawing code into a single loop and
adds the required methods to the event iterator to support this. In the
common case now (cached colors and no label) there are no event type
lookups required and things are about 30% faster. By having just a single
loop it will make it easier to add the 'merged' drawing in a future CL
(which can draw about 9million events in 30ms instead of 1.5s).

Fixed an issue with the zone painter not being tall enough to hit test
instance events properly.
Merge pull request #292 from google/speedupzone

Speeding up zone painting.
Cleaning up the help dialog.
Good enough for shipping!
Fixes #289.
Merge pull request #293 from google/help

Cleaning up the help dialog.
Speeding up event statistics.
This flips the way the event statistics tables work around a bit to allow
for 'free' filtering and caching of the full table. The only time a new
table is generated is when the selection changes, and only when it's not
a select-all.

With this, filtering on even 9 million entry dbs is instant (so long as
the paint times are low).

Fixes #283.
Merge pull request #294 from google/faststats

Speeding up event statistics.
Draw grey proxy boxes for very thin scope stacks.
This makes drawing the main view dependent on screen size, not trace size.
Fixes #272.
Merge pull request #296 from google/fastdraw

Draw grey proxy boxes for very thin scope stacks.
Adding actual options parsing to instrument.js.
Merge pull request #298 from google/opts

Adding actual options parsing to instrument.js.
Updating version to 2013.3.13-1.
Adding info about --track-heap.
Throw up an alert() when allow-natives-syntax is not turned on.
Work on #299.
Update call_tracing.md
Update call_tracing.md
Removing the old closure-library source.
Using the latest closure-library from the official git repo.
Fix for new @deprecated showElement -> setElementShown.
Latest closure linter.
Update README.md