Rename module to ngBootstrap.dateRangePicker

Renames ngBootstrap to more appropriate ngBootstrap.dateRangePicker
Add locale attribute
Remove $render function

Now you have to show the dates manually which gives more flexibility
Bind model to native Date objects

ng-model now has two Date objects, not two momentjs objects, which
unties you from momentjs and simplifies $watching.
Update documentation
INCR version to 0.0.3
Update samples