tune up Candidate/Interview pages

1 support assign job opening in new candidate page
2 change column for candidates list page
3 support some column ording for cadidates list page
4 support interviews' pagination

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge branch 'master' of https://github.com/vmw-tmpst/heroapp-LetsHire into interview

Signed-off-by: Henry Chen <hchen@vmware.com>

Conflicts:
	app/assets/javascripts/candidates.js
UI bugfixes
Merge pull request #196 from Henry-CF/interview

tune up Candidate/Interview pages
Merge pull request #197 from wgu/master

[48482551, 50159053] save button not aligned, underscore is not shown
repair spec
Merge remote-tracking branch 'vmw-tmpst/master' into fix-bug-49582201

Conflicts:
	app/views/openings/_form.html.slim