Support for ImageData instantiation using a source array

[lualparedes]

This PR introduces changes in the ImageData class to comply with the official specification.

Changes

• ImageData() now supports instantiation using the syntax: new ImageData(array, width [, height]);.
• More semantic error types.
• Test suite for the class was refactored, each inner describe block corresponds to each valid way to instantiate ImageData. All tests from the previous version are in the first inner describe block.

[coveralls]

Coverage remained the same at 100.0% when pulling 44a1df8 on lualparedes:master into 7d6239c on hustcc:master.

[coveralls]

Coverage decreased (-0.07%) to 99.931% when pulling 27624eb on lualparedes:master into 7d6239c on hustcc:master.

[jtenner]

Wow. At first glance, this looks great and comprehensive. The test suite meets my expectations, and it appears to follow the specification.

I will take some time to read the specs and go over the algorithms to look for some improvements, and inspect why coverage is reported at 99.931%. (Very strange.)

[lualparedes]

Hi @jtenner, thanks for replying quickly.

The coverage issue was caused by a single line that wasn't covered because of a small typo in the test suite. The issue was fixed in the second commit.

[hustcc]

@jtenner You can decide whether to merge the PR or not. And what is your npm id, you can help to release the new version.

[jtenner]

Thank you @hustcc.

I really like this pull request. Just want to give myself a little time with it to make sure everything is truly covered.

The honest truth is it was a total oversight of mine not to have included it in the first place :)

[jtenner]

Alright! Looks good. I'm pretty confident this will be okay in production. It's just that this software was downloaded 88k times this week, and I wanted to sit on the pull request until I was absolutely confident it would be okay.

@hustcc we can release a minor update 2.2.0.

Is it possible to get access to publish this on npm as well?

npm id: jtenner