Updating tagsoup to 1.2.1
Covering case insensitive doctype with tests.

There's been at least 2 issues (#15 and #40), so that sounds like a pain point for some users. Added a test that verifies that case-insensetive doctypes are handled correctly.
Fixing .travis.yml configuraiton
Merge pull request #54 from ifesdjeen/tag-soup-1.2.1

Tag soup 1.2.1