Add case insenstive check for HLS playback

[leandromoreira]

It fixes #1522

[coveralls]

Coverage decreased (-0.5%) to 77.945% when pulling 592262b on mimetypes-case-sensitive-1522 into e55c8fe on master.

[leandromoreira]

the build is passing locally =/

Chromium 62.0.3202 (Ubuntu 0.0.0) ERROR
  {
    "message": "Uncaught AssertionError: expected false to be true\nat node_modules/chai/chai.js:239:7\n\nAssertionError: expected false to be true\n    at test/playbacks/html5_video_spec.js:5030:27\n    at setResult (test/playbacks/html5_video_spec.js:823:71717)\n    at test/playbacks/html5_video_spec.js:823:71257",
    "str": "Uncaught AssertionError: expected false to be true\nat node_modules/chai/chai.js:239:7\n\nAssertionError: expected false to be true\n    at test/playbacks/html5_video_spec.js:5030:27\n    at setResult (test/playbacks/html5_video_spec.js:823:71717)\n    at test/playbacks/html5_video_spec.js:823:71257"
  }

Firefox 62.0.0 (Linux 0.0.0) HLS playback can play regardless of any mime type letter case FAILED
	expected false to be true
	AssertionError@base/node_modules/chai/chai.js?40e7aa72e9665366bfd82579520de4fb0754dfae:9320:13
	[3]</module.exports/Assertion.prototype.assert@base/node_modules/chai/chai.js?40e7aa72e9665366bfd82579520de4fb0754dfae:239:13
	[5]</module.exports/<@base/node_modules/chai/chai.js?40e7aa72e9665366bfd82579520de4fb0754dfae:1020:5
	propertyGetter@base/node_modules/chai/chai.js?40e7aa72e9665366bfd82579520de4fb0754dfae:7784:22
	proxyGetter@base/node_modules/chai/chai.js?40e7aa72e9665366bfd82579520de4fb0754dfae:9128:14
	@base/test/playbacks/hls_spec.js?133d39286f4675f45c2874b70d94d70b31cbb23a:24539:5

My firefox is 62.0.3 (macosx) though. It seems something related to chaijs

[towerz]

@leandromoreira I changed the travis configuration to use Chrome instead of Chromium. The problem with the tests seems to be related to running on an earlier version of Chrome/Chromium. Please rebase the branch to fix the PR checks.

[towerz]

@leandromoreira I took the liberty of removing some duplicate commits coming from another PR. The test is still failing, I'm not sure why.
I'll have a better look at this tomorrow, since I cannot reproduce the failure on either my Mac or Windows machines, so I'll have to run them on Linux and see whether I can find out what's going on.