Add --only option for running a single cop.

This is very useful for debugging, and probably good for end users
as well.
Merge pull request #142 from jurriaan/small-fixes

replaced if array.find {} with if array.any? {}
Merge pull request #140 from jonas054/only_option

Add --only option for running a single cop.
Extract some specs which are related to project rather than CLI
Run CLI specs in isolated environment

Previously, the specs were run in the project directory.
This fixes #119.
Fix odd indentations
Remove unnecessary test directory creation
Change FileHelper#create_file to add line feed to end of file
Refactor CLI specs with FileHelper#create_file

fix #133

fix #133 and #136
Refactor Alias cop
Add new cop Not
Simplify a bit the ClassMethods cop
Add new cop Eval
Revert "Use sensible default configuration"

This reverts commit 25398336579b48c17cd8e812cacf71f7461b668c.
Fix broken specs caused by calling #for_cop for Hash instance
Fix SymbolArray cop is not properly disabled by default

This fixes #137.
fix #133, #136 and refactor
replaced if array.find {} with if array.any? {}
Add --only option for running a single cop.

This is very useful for debugging, and probably good for end users
as well.
Merge pull request #138 from zeroed/master

fix #133