Added NSExceptions to Grid Generators and

moved audio files to strings
finished test cases
Added line about what spam is for bounce & sort
copied over storyboard template for instructions

added text of instructions
finished looking up instructions to game
Changes addressing comments.
Merge pull request #63 from zsweedyk/feature-validInputTests

Feature - unit tests that check for valid input.
Addressed Paula's comments.
Merge pull request #68 from zsweedyk/feature-PID-instructions

Added PID Instructions + changed Spam Instructions
Added transparency to the level complete pop up.
Changed nil check to negative
Merge pull request #75 from zsweedyk/bugfix-validInputTest

Changed nil check to negative
Adjusted font on the storyboard.
Merge pull request #76 from zsweedyk/feature-level-end-aesthetics

Feature level end aesthetics
Merge branch 'develop' into feature-finishInstructions