Fix history_state failing when RequestHandler and parse json extension are enabled
Update travis.yml to use PHPUnit 3.7

Travis recently updated to phpunit4 which doesn't play nice with
DebugKit, install phpunit3.7 which works.
Update tags DebugKit is tested against.

Use the most recent 3 releases of 2.x.
Replace 0px with 0.

Closes #164
Merge pull request #162 from augusto-cdxs/master

Fix history_state requestfailing
wrong sqlPanel id
Merge pull request #168 from joostdekeijzer/explain-sql-jquery-selector-fix

wrong sqlPanel id prevents explain sql link from working
String cast log data.

Failing to string cast data like Exceptions causes errors when restoring
log state as exceptions may contain Closure objects in their stack
traces.

Fixes #165
Remove tabs and newlines from SQL fed into explain links.

Having new lines and tabs in SQL explains can cause the links to not
work properly.

Fixes #140