Rename getSlug to slug

another 2 % of #2124
- renamed `/ghost/api/v0.1/posts/getSlug/ to
`/ghost/api/v0.1/posts/slug/`
- renamed method getSlug to generateSlug
Add functional tests for admin navigation bar and menus

issue #2273
- Check that menu nav items exist
- Check that menu nav items are labeled correctly
- Check that menu nav items have correct URLs
Cache invalidation for tag pages
Updating Ghost-UI to 0.1.3
Version bump for 0.4.2
Fixing showdown link to work without git
Added populate last login time

closes #2515
- sets last_login when user is saved if user status changed to active
- added integration test in user Basic Operations
Fixes tag cache test issues introduced in c6c4d5a8
Merge pull request #2519 from halfdan/tag-cache

Fixes tag cache test issues introduced in c6c4d5a8
Merge pull request #2439 from sebgie/move-slug

Rename getSlug to slug
Fixed check for a theme's custom error.hbs:

Closes #2513
- Checks for property `error.hbs` on active theme
- Added unit test to ensure `error` view is rendered when activeTheme has
  a custom error template.
- Removed unused variable, `userErrorTemplatePath` from errorHandler
- Refactored errorHandler.`updateActiveTheme` to take one argument, the new active theme, and to then check if the active theme has an error.hbs
- Changed errorHandler unit test to use rewire for mocking config.
Adding database to bug report template
Update README & Contributing with details of stable branch
Adding .bowerrc

If no .bowerrc file is found in the current folder it seems to lookup if one exists in parent folders. Thus, we need to use .bowerrc in order to avoid problems.
Merge pull request #2386 from manuelmitasch/add-bowerrc
Server start refactor, route tests use ghost app

closes #2442, issue #2182

- Server start refactored - messaging is just messaging, deferred resolves the httpserver so that the connection can be closed
- Updated travis config to set node env
- Updated example config to be less travis-specific
- Route tests updated to use this new functionality
- Grunt test-routes simplified
Merge pull request #2500 from ErisDS/issue-2442

[WIP] Server start refactor, route tests use ghost app
in some cases the git protocol cannot be processed (port blocking or other reasons) with https it should work for everyone
Merge pull request #2450 from jaswilli/issue-2273

Add functional tests for admin navigation bar and menus
Merge pull request #2516 from novaugust/last_login

Added populate last login time per #2515