Adding style settings file for use with Objective-Clean app.

Objective-Clean app is used to maintain code style consistency and can be downloaded here: http://objclean.com
Updating gitignore with some more Xcode specific restrictions
Outlining and documenting the new AGKMatrix class.
Filling out the AGKMatrix implementation.
Started constructing tests for AGKMatrix

Also added matrix comparison methods.
Adding tests for "Counting Entries" and some of "Accessing Members, Columns and Rows"
Finished tests for "Accessing Members, Columns and Rows"
Added some tests for "Adding Members, Columns and Rows"
Finished tests for "Adding Members, Columns and Rows"
Added tests for "Rearranging Members"
Added tests for "Deriving New Matrices"

Fixed issue with `-[matrixWithColumnSize:rowSize:andTranspose:]` where the new matrix was not as expected by the test.
Changed tests to use the `setUp` method.
Added test for "Matrix Operations"
Added insertion methods for AGKMatrix columns and rows.
Changed `setColumnAtIndex:` and `setRowAtIndex:` to accept a nil members parameter, and fill the specified index with default placeholders.
Added Categories for GLKit and CATransform3D matrices

Also added tests for the CATransform3D category.
First attempt to integrate perspective transform in demo project
Expanded AGKMatrix to handle Determinants, Cofactors, Adjoint, and Inverse operations.
Added vector 3D multiplication to AGKMatrix
Added matrix multiplication.