PEP8 code cleanup
Merge pull request #15 from holiman/master

Documentation markdown
Merge pull request #16 from holiman/master

Improved built-in help
Merge pull request #14 from georgemarshall/master

PEP8 code cleanup
minor fixes

Including: correct initial options values, fix menu to work with
keyboard, fix Options dialog to work with Tab key, fix memory leak from
Options dialog.
RFIDler Monitor for Windows minor fixes
RFIDler Monitor for Windows fix Options dialog bug

'None' button did not work correctly for Notifications tab.
Also add a 'Default Values' button to the dialog.
- Added functionality to dump a reading:

	#./rfidler.py /dev/RFIDler 'set tag askraw' 'potset h 150' 'set fc 745' 'set rate 33' dump 6000
	sending 'SET TAG ASKRAW'
	sending 'POTSET H 150'
	sending 'SET FC 745'
	sending 'SET RATE 33'
	Wrote dump to dump_20141121-075357.xml

- Added functionality to plot from a previously saved reading:

	#./rfidler.py /dev/RFIDler load dump_20141121-075357.xml

- Added some logic to print out bit periods, i.e. the number of samples before the next toggling (not the true bit period, just to help determine the true bit period)