Add missing Backbone import in core
Replace lower/upper bound of number range control with min/max

This commit also cleans up the references to the lower and upper bound
inputs by adding references to them in the ui section and using that
reference instead of looking them up with a selector on each reference.
Fix naming issue in logging import in core
Add date and time simple types to those that open the DateControl

Avocado supports all three so it is possible we will see any of them and we should use the DateControl for all three of them.
Fix bad use of Number function in the number control
Create a ui reference to replace the help text selector
Fix persistence problems in the number control

Overall, the control was very fragile before and could easily get out of sync if you clicked between controls too fast or if you re-opened the control after browsing to a different control. These issues are now fixed by correctly handling the 3 situations where the bounds might need to be changes: stats reset, onRender(), setValue().
Add a ui reference to replace the upper/lower bound input selectors
Consolidate number- and date-range-input templates into one template
Add a generic range control and modify number to extend it
Add overrideable methods for parsing the min/max in the range field stats
Refactor the date range control to extend generic range control
Merge branch '2.1' into issue-269

Conflicts:
	src/coffee/cilantro/core.coffee
Fix type in parsing method name in date range control
Add justification for mysterious replace in min/max parsing method
Use parseFloat() instead of Number() in numeric range control
Add separate methods for setting placeholder and value
Extend range events in date range control
Merge pull request #277 from cbmi/issue-269

Replace lower/upper bound of number and date input controls with min/max