LeapHttpClient verifies hostname.

This fixes #3287
Backstack OK from notification bar.

Pressing back after entering Dashboard from notification bar, the user
goes back to home.
Retains username if login process failed.

New login dialog shows the original username, so that if the user failed
writing his/her password, s/he does not have to write again the
username.
ProviderAPI intent receives actions and parameters.

We no longer use BundleExtras named as the action ProviderAPI is
intended to perform, but we standardise this name
(ProviderAPI.PARAMETERS), and use setAction to pass that action string.
FileNotFoundException catched in all downloads.

Added a new catch block in all downloads methods.
EIP fragment is replaced if provider is switched.

We were checking if eip existed before adding it again, but that check
can be removed if we make a replace instead of an add.
Disallow export of EIP service Intents
Use java.security classes to validate string certificates and keys from provider
Added a progressbar to ConfigurationWizard.

It resizes the provider list, pushing it down to show the progressbar
up, and back to the original layout after the operation.
Removed a silly toast that should not be shown.
Dashboard progressbar lives below the status line.

I've renamed configuration wizard progressbar, because both had the same
name and that provoked a conflict.
ProviderAPI broadcasts progress for log in process

Login progress bar advances according to the srp stages.
ProgressBar xml is loaded correctly.
Login and Logout progressbars advance correctly.

Next step: prettify.
Holo theme for CW progress bar.