Merge pull request #3 from allending/master

issue #2 - improve look of calculator and add .gitignore
Merge pull request #5 from allending/master

issue #4 - add buttons  -_-
source merged from previous my calculator 2nd, and added function, except decimal point . -_- why am i doing this in the morning
fix M* related edge cases
issue #6 - remove storyboard warnings