View all schedules for a job

Add a view to resque-web to list all the timestamps for which a given
job is scheduled.
FIX: add missing table row

Each timestamp need to be wrapped in a table row.
Basic test for GET /delayed/jobs/:klass

Add a basic test for the new view. It just check for an OK response.
Base64 is not used in resque scheduler's server

Remove unnecessary require for base64.
Better encode job arguments

Use URI library to escape the url for listing all schedules
for a given job. Argument are now encoded as JSON to be able
to correctly handle integer and string parameters.
Add a test for web delayed schedules

Add a spec for the added view showing a list of all the timestamp at
which a given job has been scheduled (delayed).
Remove 2 offences detected by rubocop

Remove offences detected by rubocop
- Avoid using {...} for multi-line blocks.
- Use %w or %W for array of words.

Thanks @yaauie to point it out.
Use ResqueScheduler::Util::constantize

Use ResqueScheduler::Util::constantize to constantize the class name.
This is to obtain the right class even for a namespaced name like, e.g.,
SomeNamespace::SomeJob.
FIX: add tests for the namespaced class

Forgot to add tests for the case of a namespaced class.
FIX: typo on 'no jobs' message

Fix wording for 'no jobs' message in the dealyed job scheduled view.
Merge pull request #282 from bugant/view-all-schedules-for-a-job

View all schedules for a job