Exclude three.js from the benchmark due to its high variance.

Now that the variance has been corrected, it reveals that an extremely large
source file causes a high variance, possibly due to the size pressure and/or
garbage collector. To maintain a high level of benchmark confidence, that
test is now excluded.

https://code.google.com/p/esprima/issues/detail?id=397
https://code.google.com/p/esprima/issues/detail?id=354
Benchmark runner: optional location tracking.

Based on the work from ZHANG Bei <ikarienator@gmail.com>.

https://code.google.com/p/esprima/issues/detail?id=412
Improve the speed of filterGroup() function.

https://code.google.com/p/esprima/issues/detail?id=413
Benchmark corpus: update jQuery, Backbone.js and AngularJS.

http://code.google.com/p/esprima/issues/detail?id=354
Merge branch 'master' into gh-pages