Fix NPE for dependency methods/groups

When a test method depends on a group/method
which doesn't exist and when a user specifies
[ignoreMissingDependencies=true] instead of running
the test method, TestNG throws a NullPointerException
Fixed this issue.

Also updated the .gitignore file to include 
class path and project eclipse files.
Merge pull request #348 from krmahadevan/krmahadevan-FixNPE

Fix NPE for dependency methods/groups