Fix issues with bower assets in tests

- Ensure that there are no spaces in path so `bower install` succeeds
- Ensure that shell:bower is executed before tests are run

Fixes #1702
Merge pull request #2578 from schneidmaster/fix-1702

Ensure libraries are present when running phantom.js test
Added functional tests for admin content screen

issue #2273
- test draft/page/published label
- test green add new post button
- test status and author in preview header
- test edit post button
- test delete modal
Merge pull request #2586 from jaswilli/issue-2273

Added functional tests for admin content screen