Include check for nil-session
Merge pull request #400 from 545ch4/master

Include check for nil-session
Clone the link so attributes are not altered - Fix #399
Clarify page:update description in README - Fix #398
Move cloning of link element inside the Link class to preserve ability to inspect surrounding elements
Add page:before-unload event - Close #401
Add Prototype compatibility with custom events - Fix #384
Maintain load order of scripts in the body - Fix #389
Provide target URL to page:before-change event - Close #357
Move event names into Turbolinks.EVENTS
expose event list via `Turbolinks.events()`

refs #403
Ignore empty hash links when the current location ends in an empty hash - Fix #407
Check if Content-Type header exists before checking its value - Fix #410
Handle HTML parsing bug in Safari 7.1 - Fix #408
Properly ignore empty hash links - Fix #407 again
Merge branch 'meleyal-events-getter'
Change Turbolinks.events() array to Turbolinks.EVENTS hash
Don't set request_method cookie for GET requests

The Turbolinks script assumes a GET request if no cookie is present, so
sending a cookie for GET is redundant. Turbolinks immediately deletes the
cookie after reading it, so there is no risk of e.g. a PUT cookie value
persisting through to the next GET request.
Merge pull request #405 from mattbrictson/no-cookie-on-get

Don't set request_method cookie for GET requests
v2.4.0