Update code coverage report.

http://code.google.com/p/esprima/issues/detail?id=388
Bump our coverage threshold.

http://code.google.com/p/esprima/issues/detail?id=388
Update esmorph.

This fixes the unescaped double quotes issue in the function tracing
demo.

http://code.google.com/p/esprima/issues/detail?id=394