Tweaked the prefs dialog ui for cosmetics. Switched from instantiating a
dialog to subclassing it in order to get better control over visual esthetics.
tweaked debug_log() to also write to stderr
Added new options: "show date" and "show year", refactored dt_format logic to suit
remove 'tz' item from default cfg data
added note reminding me that the show_* vars within the prefs dialog are
not in fact the actual settings but are the widgets instead. Probably
should have just renamed the widget variables
removed a commented line of code and updated debug_log messages
TailsClockConfig - abstracting configuration settings and files.
Use the new TailsClockConfig class
whitespace cleanup
Refined scheduling of next applet "tick" so that there's less logic
and more dependence upon datetime's math/delta handling
Code doc for update_glib_timer method
refine and abstract the dt format mechanics, also, use the new mechanics
Added "Copy Date" and "Copy Time" to the applet's context menu.