Merge pull request #157 from radcortez/master

Refactored batch tests to use CountDownLatch
Extended README with some contribution guidelines.
Missing parts:
* test methods naming convetions (as it is still part of ongoing discussion)
* preferred libraries
Enhanced .gitignore
Changes mainly for netbeans and intellij. Plus some small cleanups.
Merge pull request #160 from bartoszmajsak/gitignore

Enhanced .gitignore
Merge pull request #159 from bartoszmajsak/contribution_guide

#147 Extended README with some contribution guidelines.