Improvements

[dhilt]

This PR includes

• scrolling flag removing
• items requesting never ends (https://github.com/Hill30/NGScroller/issues/64) fix
• some minor refactoring
• a new adapter introducing

The last one is a complex issue, it includes a detailed demo: http://rawgit.com/dhilt/NGScroller/improvements/src/examples/adapter.html

[dhilt]

It would be better to change minor version of the product after that I suppose. To v1.1.0.