Merge pull request #20 from zsweedyk/release/0.1.0

Release/0.1.0
Updated method signatures to be of the form "- (instancetype)initWithWidth:(CGFloat)width height:(CGFloat)height;", as in the Ray Wenderlich style guide. Changed text to be compliant with the 100 column limit. Choosing row over r. Removing extraneous comments, especially for functions that are just getters. Maintained 1 line separation between functions. Moved imports to header files. Added team member name to file header.
Minor changes to fix the syntax from Paula's comments on pull request. Added efficiency gains for for loops, pulled out call to [x count] from loop.
Style consistent modifications to views, openings
Slight style corrections for views.
More space fixes
Revised if statement indentation.
Merge pull request #21 from zsweedyk/feature-syntax-model

Made changes to syntax as per agreed upon style guide.
Style nit - removed unused variable
Merge branch 'develop' into feature-syntax-views
Style nits - spacing.
Merge pull request #22 from zsweedyk/feature-syntax-views

Looks good to us!
Abstracts BFS in GridModel
Breadth first search of connected cells in GridModel is abstracted, so that the actions that deal with connected cells can be specified in individual functions without repeating implementation of search.
Added infection and visibility features. Tested them. They work.
Added persistent level unlocks.
Replaced the LevelSelectionViewController's storyboard buttons with programmatic buttons, which get enabled or disabled based on an NSUserDefault integer representing the highest level unlocked. Updated the LevelViewController to update this integer when a level is completed.
Renamed function.
Extracted numLevelButtons constant to the class level.
Style corrections.
Merge pull request #23 from zsweedyk/feature-abstract-BFS

Abstract BFS in GridModel
Merge pull request #26 from zsweedyk/feature-level-unlocking

Added persistent level unlocks.
Updated tests, added constants to GridGenerator, fixed positioning of global constants in CellView