Fix #7 support for dev=1 and version=... in query string

Some code changes + removal of AT 1.3.5 + add AT 1.3.7 and AT 1.4.4

Quick tests:

http://jakub-g.github.io/instantat/?dev=0&version=1.3.7
http://jakub-g.github.io/instantat/?dev=1&version=1.3.7
http://jakub-g.github.io/instantat/?dev=0&version=1.4.4
http://jakub-g.github.io/instantat/?dev=1&version=1.4.4

(defaults: dev=0, version = 1.4.4)