Client Certificate Authentication
Merge branch 'master' into tls-client-cert-auth

Conflicts:
	src/com/fsck/k9/fragment/ConfirmationDialogFragment.java
Fixes needed after merging in master

Also, fix unit tests.
Clean up indentation

White space changes only.
Rework validateFields() and updateViewFromAuthType()

Previously, it was possible to have "Require sign-in" unchecked and a
"Security = None" setting for the outgoing server and still not be able to
tap "Next" because of a hidden (and irrelevant) "Authentication = Client
certificate" setting.

Check that the user has actually chosen a client certificate in
AccountSetupOutgoing.validateFields().

Also, there's no need to clear the password and certificate fields when
hiding them.  The user may accidentally change settings and want to change
them back without wiping out the existing settings.
Notify user of invalid account-setup settings combo

Specifically, warn and block them when attempting to configure Client
Certificate Authentication in combination with Connection Security = None.

If this were not made obvious to the user, they might not understand why
they are not permitted to tap "Next".

Also, move the initialization of all view listeners out of onCreate() into
initializeViewListeners() which is then called near the end of onCreate(),
helping to assure that the listeners won't be triggered during the
initialization of views inside onCreate().
Configure mail notifications by folder class

In response to Issue 1794,
- add a configuration option in the account preferences to show
  notifications only for 1st/2nd/etc class folders
- add an option in the folder preferences to set the notification class
  as 1st, 2nd or inherited from the folder's push class

The default behaviour remains unchanged.
Reorganize the server setup layouts

This only changes the vertical display order of the widgets.

The user will likely review the settings from top to bottom, but
the way they were previously arranged, settings lower on the list
were affecting things higher on the list.

Generally show top to bottom:
Server
security type
port (affected by security type above)
require login checkbox (SMTP only, affects everything below)
user
auth. type (affected by security type above, affects everything below)
password (affected by auth. type above)
client cert (affected by auth. type above)
Refactor KeyChainKeyManager()'s sClientCertificateReferenceWorkaround

The referenced issue states that it is only applicable to Android < 4.2
(testing confirms the problem on 4.1.2, but not on 4.2.2).

A test was added for the version code, primarily as a finder's aid for a
day when K-9 Mail no longer supports Android < 4.2 and the work-around can
be removed.

The referenced issue also states that it is only necessary to hold a
reference to the first PrivateKey retrieved. (Testing indicates that the
problem is avoided so long at least one reference is always maintained to
a PrivateKey -- it doesn't actually need to be a continuous reference to
the first PrivateKey.)

From my understanding, a normal class loader never unloads a class, so the
static reference can be safely kept privately in KeyChainKeyManager.
Import/Export client certificate alias setting
Avoid NPE on export

Occurs when the SMTP server doesn't require authentication
(authenticationType == null).

The javadoc for ServerSettings says that both authenticationType and
connectionSecurity may be null.
Fix so WebDAV does not have STARTTLS auth. type option
Fix WebDAV manual account setup

When creating a new account, the Incoming Server Settings screen
was initialized with the user name = PLAIN.
Fix password prompts on account import

Don't prompt if server's AuthType == EXTERNAL

Don't prompt for SMTP servers that don't require authentication
(no user name).
Fix outgoing server settings display

Add test for username == "".

Without it, the mRequireLoginView remains checked, and the empty username
and password boxes are not hidden.

The problem occurs if importing an SMTP server that has an
authenticationType, but no username or password (i.e., no authentication
required).

That's the way settings were exported in 4.904 and before.
Don't trigger validateFields() except on user input

Previously, with settings of Security=SSL and authentication=certificate,
attempting to change Security=None would (of course) be blocked.  So
Security would remain SSL.  But the authentication options would then
include "Password, transmitted insecurely", whereas the option should
have remained as "Normal password" (because the security remained SSL).

The problem could have been fixed with a simple shuffling in
updatePortFromSecurityType() so that updateAuthPlainTextFromSecurityType()
was invoked before mPortView.setText(), but the logic for requiring that
ordering was not plain to see.  (Although no longer necessary, the
shuffling was done as well.)
Save/Restore activity state

This assures that changes made to the port setting and to the chosen
client certificate are saved and restored.
Don't clear widgets when removing

The user may toggle the checkbox, and then decide to toggle it again.

This also fixes a problem when restoring the activity state.  When the
checkbox was restored as checked, the listener was firing and wiping the
the restored alias.
Revert unused code changes
Use theme based style