Fix TravisCI for node 0.11

[gutomaia]

According to Travis[1], nodeNES has a problem using node 0.11 due to canvas. That problem should not bother the final user, since there is no canvas dependency for the final user, but it does break our tests.

Stackoverflow might have a clue about it.

The Goal is to fix this issue using node 0.11 and run it on Travis on your branch before merge.

[1] https://travis-ci.org/gutomaia/nodeNES/jobs/24391052
[2] http://stackoverflow.com/questions/14947691/c-system-file-bits-stat-h-suddenly-breaks-with-error-field-st-atim-has-inc