Prepare for new gem release.
Typo fixes and re-adjusted version.

Adjusted version number after discussion with @jzaleski, he caught my failure! :)
Get the retry_attempt for DirtyExit failures, where perform isn't called.

@retry_attempt depends on perform being called, but perform will be called
after forking and set in the child job process. If there is a crash that
prevents the job from notifying the failure hooks itself, then a DirtyExit
exception will be given to the on_failure hooks from a worker processes,
where @retry_attempt will not have been set.

The @on_failure_retry_hook_already_called variable also needs to be
ignored, because this is set to false in the before_perform hook.
Add test for retry attempt being accurate for dirty exit failures.
Merge pull request #61 from dylanahsmith/dirty-exit-retry-attempt

Get the retry_attempt for DirtyExit failures, where perform isn't called.
Update history and version ready for gem release v1.3.1
`#constantize` is on `Job`
Merge pull request #109 from michaelglass/fix_constantize

`#constantize` is on `Job`
Update README.md

Improved README.md to explain the steps needed to start the 'resque-web' server interface properly with the 'resque-retry' features. 

The problems as I identified them essentially were: 
A. The README proposed a rack configuration, but didn't include an example command for a user to start the server. Solution: Added a simple example on how to start the server with bundler by loading the proposed rack configuration. 
B. The README didn't include the alternate option of starting the resque-web interface using the built-in 'resque-web' command. Solution: Included a simple 3 step explanation on how to use the resque-web command by sending it a configuration file as a parameter
Update README.md

Updating the README section on resque-web: rackup example is now mentioned first, and includes a simple example of how to run the server with rackup (with and without bundler). Updated description and tried to clean up the markup for the resque-web section.
Update README.md

Removing breaklines from step-by-step resque-web example
Update README.md

Replacing the step-by-step example for using resque-web, to something simpler (while avoiding markdown craziness).
Update README.md

Explicitly displaying that user must require his application code when using config.ru.
Update README.md

Updating README so that resque-web example also includes comments on where to require worker and application code.
Update README.md

Removed the '.rb' from the require in the "Configuring and running the Resque-Web Interface".
Prepare for v1.3.2 gem release.
Merge pull request #110 from mindware/patch-1

Update README.md