12hour inputchange

Adds 12 hour AM/PM support, enabled by new option "show24Hours" set to false (default true). This and other new 12 hour options are based on timeEntry by @kbwood (https://github.com/kbwood/timeentry), with which clockpicker works well - see the fiddle http://jsfiddle.net/gitlost/WXD3x/ for an example. The clock hours have been left as is, in 24 hour format - may be confusing.

Adds new option "immediateset" that sets the input as soon as the clock time changes, with setting input from time factored out into a new function, setInput(). Makes picking on the hour times a one-click op.

Also adds tracking input changes with new event handler inputChange(), with setting time from input factored out into a new function, getInput(). Useful when using timeEntry.

Also adds event "clockpickerdone" which is triggered after clockpicker sets the input in done() - generally handy (as mentioned by @vv3d0x in #7) and avoids having to listen to "change" in timeEntry case.