Remove hard-coded release date from gemspec (which means that we'll use the default which is ).
Use new ruby_parser 3 and friends

Removes ripper_ruby_parser as a dependency, and the code that implements
choosing the parser implementation.
Bump version to 1.3.
Update travis notification receivers.
Added command-line option for printing line numbers with the smell lines.
Merge pull request #129 from troessner/AddShowLineNumOption

Added command-line option for printing line numbers with the smell lines...
Updated dependencies to use ruby2ruby 2.0.2 and ruby_parser 3.1.1 to avoid version conflict with ruby2ruby when using 2.0.2.
Merge pull request #130 from geoffharcourt/ruby_parser_3_1

Updated dependencies to use ruby2ruby 2.0.2 and ruby_parser 3.1.1
Added smell for nil checks
Merge pull request #131 from troessner/AddCheckNilSmell

Added smell for nil checks
Bump version to 1.3.1.
Fixed nil-checker output with -n flag
Merge pull request #133 from EmilRehnberg/FixLineNumberOutputForNilCheck

Fixed nil-checker output with -n flag
Improve generated default settings list