cfme login tests work if the browser is already logged in

Also caught a bug on is_displayed: `browser()` (a WebDriver) has no
`is_displayed` method.
force_navigate now passes args (like context) back to go_to
Database creds are in the yamls now, thanks to #422
provider setup functions for infra and cloud
Merge pull request #419 from seandst/login

cfme login tests work if the browser is already logged in
Merge pull request #420 from seandst/force-nav-passes-args

force_navigate now passes args (like context) back to go_to
Merge pull request #424 from seandst/database-credentialols

Database creds are in the yamls now, thanks to #422
Merge pull request #425 from seandst/provider-setups

provider setup functions for infra and cloud
Merge pull request #421 from seandst/tabstrip-form

TabStripForm
ensure_browser_open can deal with open alerts now, but is still pretty ruthless

force_navigate also got some nicer logging
Merge pull request #427 from seandst/force-navigate

ensure_browser_open can deal with open alerts now
TabStripForm also supports the fields arg

In the course of actually using this, I learned that you couldn't
submit a tabstrip form with a submit button. :(