Workaround so only one CTRL-C is required for a new prompt in --gui=qt

Only implemented for posix systems. On Windows SIGINT kills python,
and signal.CTRL_C_EVENT doesn't do anything.
Changed sleep in signal thread to .01 sec. Moved imports to top.
Use python timers instead of thread + sleep
keep track of the sigint timer, and cancel it on a new prompt
Added comments explaining the SIGINT timer
Made sigint_timer and got_kbdint module globals
Improving the tab completion UI/design
Updating box-shadows to proper bootstrap less function.
Removing old autogrow JS code.
Removing printnotebook template.
Removing printnotebook JS code.
Removing stale call to print view in JS.
Removing print notebook less code.
Removing print handler.
Removing print handler and URL regepx.
Removing print notebook from style.less.
Updating style.min.css.
Merge pull request #3234 from ellisonbg/removegrow

Removing old autogrow JS code.

it is no longer necessary
Merge pull request #3233 from minrk/scrubprefix

check prefixes for swallowing kernel args
Merge pull request #3231 from minrk/localipsagain

improve discovery of public IPs