Implement Several Small Improvements

[JackSekoranja]

This PR implements the following changes in preparation for todays UAT:

• Elective Rule:
  • Default value is now 24 instead of 0
  • Values of 0 are now considered invalid (Can't complete 0 units of electives)
  • Minimum value of the unit scroll option is now 6 instead of 0
• Course Selection Rule:
  • Removed debug print statement
  • When choosing from the Minimum and Maximum option, a minimum of 0 is now valid
  • Error messages now disappear as soon as they are fixed
  • Standard and Max unit count boxes now have the minimum set to 6 instead of 0
• Custom (Text) Rule:
  • Default value now set to 6
  • Added verification on
  • Minimum value of the unit scroll option is now 6 instead of 0
  • Step value was set to 6 for unit count