Merge pull request #4 from gupta-ankit/master

Changed the compiler version used by maven to Java6
Merge pull request #5 from gupta-ankit/master

Added tests for floating addition and String
Updated to ANTLR 4
Merge branch 'master' of github.com:jrguenther/shiro
Added sample code for testing parts of the grammar
Updated pom to use ANTLR 4.1
Added ANTLR4 grammar
Removed bangs from grammar
Upgraded to antlr 4.1 from 4.0
Added basic definition pass and graph building pass
Add pass code
Added beginnings of expression events
Graph only test file
Added node production listener
Interpreter now works with ANTLR4
Updated readme for antlr4
Fixed spelling mistake
Add sample code
Added subjunctive node realization
Added subjunctive node evaluation