Add version information

1. Modified the header to take advantage of Bootstrap, and removed the now-unused CSS.  Adjusted styling so the app still looked correct.
2. Converted the logout link to a drop down with Version and Log Out links.
3. Clicking Version opens a modal that displays both the client and server versions.  This is so QA can copy/paste them into a JIRA.  I've included the appreviated hash, branch-name and the date it was updated.