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
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
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