Set default for instructor computer constraint radiobutton; remove trailing whitespace
Set instructor computer constraint default; correctly set value (bool() does not work for discerning between "True" and "False")
Add okay_to_add_constraint function which calls constraint_adding_conflict and check_constraint_exists;
Rewrite constraint_adding_conflict to account for computer constraint;
Swap return values of constraint_adding_conflict (now returns True if constraint does add conflict) and check_constraint_exists (now returns True if constraint does exist);
Rewrite all relevant functions to account for this switch;
Make whitespace uniform, remove trailing whitespace
Merge branch 'develop' of https://github.com/donnell74/CSC-450-Scheduler into computers

# By Hana Baldwin (9) and Gregory Donnell (1)
# Via Gregory Donnell (1) and others
* 'develop' of https://github.com/donnell74/CSC-450-Scheduler:
  adjust display of approximate runtimes on gui
  add disclaimer, remove version info
  reduce amount of if statements for runtime value check
  adjust gui text to show that runtime options are approximate
  Remove comments made for debugging
  fix custom input error with tkMessageBox
  add custom input error checking for string/characters
  fix custom input to prevent negative/float errors
  add gui side of runtime option
  Added time logic for evolution loop in the backend, still needs gui logic

Conflicts:
	genetic/scheduler.py
Merge branch 'develop' of https://github.com/donnell74/CSC-450-Scheduler into computers

# By Daniel Hebrink (5) and Gregory Donnell (2)
# Via Daniel Hebrink
* 'develop' of https://github.com/donnell74/CSC-450-Scheduler:
  ToolTips only for windows.
  Fixed generate_starting_population being part of the time taken from time_limit
  Fix call to globs.mainScheduler inside Scheduler class
  remove extra call to evolution loop that may have been causing bad results
  Fix indent block for adding mandatory constraints
  Adding mandatory constraints moved to globs.py. Fix repeated calls to gen_start_pop()
  Clean up a bit in guiConstraints.py, add if_exists check in scheduler.py:add_constraint()

Conflicts:
	gui/guiConstraints.py
Format 'time left for evolution loop' to truncate decimals
Merge branch 'develop' of https://github.com/donnell74/CSC-450-Scheduler into develop

# By fquashie
# Via donnell74 (1) and fquashie (1)
* 'develop' of https://github.com/donnell74/CSC-450-Scheduler:
  Fixed the lab-algorithm