Enhancement: Enter a future time to set timer length

[GoogleCodeExporter]

cooktimer currently allows the user to set the timer length (i.e. the amount of 
time the timer runs) directly.  I would like to be able to enter a future time 
value so that the timer length is determined by the difference between the 
entered time and the current time, where the current time is determined when 
the user clicks Start.

For example, if the user enters 13:01:01 for the time and the time is 11:00:00 
when the user clicks start, the timer is set to run for 2:01:01.  A 24 hour max 
could be assumed, such that if, instead, the time is 23:00:00 when the user 
clicks start, the timer is set to run for 14:01:01.

Original issue reported on code.google.com by [email protected] on 19 Oct 2011 at 7:47