Changed unchecked element access to use square brackets (operator[]).
Changed unchecked element access back to operator(), created overloads up to 12 indices.
Also created constructor overloads up to 12 indices.
Created overloads of resize method up to 12 indices
Merge pull request #1 from emstoudenmire/master

Wrote out overloads for element access and resize up to 12 indices. Fixed a few other typos and added comments for all methods.