WIP: Add support for multiple browsers, logging skipped, and grouping by test suite

[weirdian2k3]

This adds a few features

Support for multiple browsers

If you run a testem test with multiple launchers, this library currently creates a valid file, but GitLab has a limitation where it can only handle one testcase for each classname and name combination. So currently, GitLab only displays the result for one of the launchers. This patch does two things to address this. First, test results are broken up into separate test suites based on launcher. Next, we populate the launcher name in the classname attribute, so that the same test in two separate launchers are no longer seen as duplicates.

Skipped tests are included in results

This patch starts allowing for the recording of skipped tests, while marking them as skipped and keeping track of the count for parent elements. This allows for proper counts of tests, skips, failures and successes.

console methods are recorded

Right now GitLab doesn't support displaying it, but this patch now records all console method calls into the system-out element

module identification

For some testers like QUnit, testem prepends the module name to the test name, separating with a colon (:) This will separate the values by the colon, moving the module name to the classname attribute