Solving coding standard violations (solved: 3528, left: 147)

Violations solved:
- 2852 violations related to 2 spaces indentation
- 5 violations related to parent class name was on new line
- 116 violations related new line after last method class
- 197 violations related wrong function declaration indentation
- 229 violations related wrong function call indentation
- 129 violations in generator

Related to: #11 

The majority left issues are in fact usage of `_` to indicate private class attribute/method. I personally use this, but it seems that PSR2 strictly forbids this.

@cordoval , should we fix that `_` as well?