Merge pull request #152 from jonas054/fix_errors

Handle regexp back references in VariableInterpolation.
Remove extra / in target file pathnames

When you passed a directory like some/ to RuboCop you got pathnames like
~/projects/some//test.rb because an extra / was added no matter whether
it was needed or not.
Update changelog
Do more caching to avoid printing same warning many times.

With the addition of support for `inherit_from`, the configuration file
loading became more complicated. A side effect was that the warning
about unrecognized cop would be printed many time per `.rubycop.yml` file.

I've changed the config caching machanism so that one cache holds
config file paths and another holds config objects. The API of the
`Config` class was changed and big changes in specs were necessary.

Fixes #151.
Simplify spec a bit
Merge pull request #153 from jonas054/print_unrecognized_cop_once

Do more caching to avoid printing same warning many times.
Bump version to 0.7.0
Fix #154 - Add missing files to gemspec
Bump version to 0.7.1
Fix for #155. A bug in Semicolon#index_of_first_token_on_line.
Merge pull request #156 from jonas054/semicolon_bug

Fix for #155. A bug in Semicolon#index_of_first_token_on_line.
`OpMethod` now handles definition of unary operators without crashing.
Use standard encoding comment
Fix broken specs
Merge pull request #157 from jonas054/op_method_error

`OpMethod` now handles definition of unary operators without crashing.
Fix for #159. Correct a bug in Cop#keywords.

In the old code we get stuck pushing and popping keywords when 'def'
is the last keyword in the list. Reworked the algorithm a bit.
Merge pull request #160 from jonas054/avoid_for_bug

Correct a bug in Cop#keywords.
Replace return with next
Fix specs
Fix bug in SymbolSnakeCase causing an exception for aliasing operators.

The sexp for an alias of an operator has a :symbol_literal node that
looks different from a regular symbol literal.