.gitignore for IntelliJ

Added .gitignore for IntelliJ
(http://stackoverflow.com/questions/16062424/dart-default-gitignore)
Fixed tests
removed whitespace
Merge pull request #3 from headinthebox/Tuesday

Gitignore & tests
Merge pull request #6 from kmillikin/master

Reorganize the translation visitor.
Add support for empty statements, prefix expression, assert, and is and as.

Also modify the command-line driver to exit rather than translate
syntactically incorrect programs.
Merge pull request #7 from kmillikin/issue-5

Add support for empty statements, prefix expression, assert, and is and ...
Super, This and ConditionalExpressions
Merge pull request #8 from headinthebox/Extra-Expressions

Super, This and ConditionalExpressions