Returned improved crawlable feature

* Improved crawlable feature turned on by default
* Fixes issue #56 rewrite `/#/url` to `/#!/url` (no more use for `/#/url`)
* Fixes issue #109 use `.on()` and `.off()` besides of outdated `.bind()` and `.unbind()`
* Specify plugin version also in development file
* Begin to add commented descriptions in development file