Streamline test structure.

Use `_test.rb` suffix for all test files. Implement `rake test` for
running all tests, updating documentation. Also change requires to not
consider `test/ryespy_test.rb` as a loading file.
Add Travis build file.
Merge branch 'testing' into develop
Build Travis for Ruby >= 1.9.2 only.
Don't build Travis against Ruby head.
Add Travis build status indicator to README.

Build passes if master|develop pass.
Don't logout of mailbox for Listener::IMAP when #close.

Since `#disconnect` is called immediately, there's no need to `#logout`,
too. Also, `#logout` fails unless logged in, whereas `#disconnect`
doesn't, so this is fine.
Test Config, fixing bug listener symbol vs string.
Implement Ryespy.notifiers, making more classy.

Instead of passing notifiers around (yrgh :| ), use the module.
Extract Ryespy Redis key prefix to Config#redis_prefix_ryespy.

Don't pass the prefix around. It's not a ball.
Refactor RedisConn connection block to check_imap|ftp.

`redis` you shall not pass.
Deprecate check_listener|imap|ftp, extracting to Listener::X#check_all.

Introduce `Listener::X#check_all`, which is called by the main loop
which all things need to be checked and processed. Set up the main
(non-notifier) Redis connection globally, rather than using multiple
connection blocks.
Merge branch 'refactor' into develop
Introduce config --redis-ns-notifiers, for namespacing Redis notifiers.

The default, which was previously hard-coded, of `resque:` is retained.
This is normally used for Resque, and works with Sidekiq. Sidekiq,
however, allows more flexibility in namespacing.

Note that it is not currently possible to use different notifier
namespaces for `Notifier::Sidekiq`, despite it being possible to use
multiple `--notifier-sidekiq` parameters pointing to different Redis
URLs.
Bump version to v0.7.0.
Merge branch 'release/v0.7.0'