Add Imaging Module acceptance tests

[zinyando]

This PR adds acceptance tests to the imaging module. It adds the tests below

• - Visit /imaging
• - Create a new imaging request
• - Test whether requests marked as completed are displayed
• - Mark an imaging request as completed

If there is something else to test please let me know.

[jkleinsc]

@zinyando It looks like one of the tests is not passing, but I think its a problem with the test, not the actual functionality. Here is the error message from the Travis CI build:

not ok 2 PhantomJS 2.0 - Acceptance | imaging: create a new imaging request
---
actual: >
Warning!!!!
expected: >
Imaging Request Saved
message: >
Imaging Request was saved successfully
Log: |
...

[jkleinsc]

Thanks for the pr @zinyando!