Implement [#7], time range selector based on bootstrap and jquery ui.

1. support available and unavailable by passing an array.
2. use 24-hour format by default.
3. refactoring, simplify api, removes global variables.
4. compatible with bootstrap theme and style
5. disable all submit button in page when user select unavailable time
range.

This widget was based on jquery-ui slider. The idea comes from
http://marcneuwirth.com/blog/2010/02/21/using-a-jquery-ui-slider-to-select-a-time-range/.

The theme comes from
https://github.com/jquery-ui-bootstrap/jquery-ui-bootstrap.

@Mask helped me to implement the original available and unavailable
time range support and rendering ui works. I spent almost a whole day to
improve @Mask's original work. Really a long journey.