Before this commit, uniqueness was checked when addding the failure. Now
we make the entiries unique when generating the error report, saving a
little time when the parsing is successful. This does not increase the
benchmark numbers too much though.
Results of benchmark with 100 runs on V8:
Before: 37.25 kB/s
After: 37.41 kB/s
Speedup: 0.241 %
Mozilla/5.0 (X11; U; Linux i686; en-US) AppleWebKit/534.3 (KHTML, like
Gecko) Chrome/6.0.472.63 Safari/534.3
The source code is now in the src directory. The library needs to be
built using "rake", which creates the lib/peg.js file by combining the
source files.