Improve TTS initialization and queuing.

Changes:
- Don't loop over all TTS locales to find if current card's language is available.
- Cut question reading when card is flipped. Start answer immediately.
- Waiting dialog while TTS initializes.
Remove unused import and invalid Javadoc
Fix calls to 'toArray()' with zero-length array argument
Cleanup .css removing invalid selectors
This is a proposed fix for bug issue 1938
https://code.google.com/p/ankidroid/issues/detail?id=1938&colspec=ID%20Type%20Priority%20Status%20Milestone%20Owner%20Summary
Merge branch 'v2.1-dev' into v2.1-dev-2nd-attempt
Removing the line that was resetting the Current deck: field in the
card editor.
When in review, if we edit a card in such a way that when we go back
to the review activity the displayed card should change (e.g. changing
the deck of the card), we need to make sure that the new card's answer
is not shown.
This is what my change makes sure of.
Delete unused layouts and classes.
Show terms and conditions with shared decks.

Currently the shared deck screen does not include the terms and
conditions, which are actually useful on that screen, as they cover the
use of shared decks.

Add them at the bottom of the screen so that they are always visible.
Clicking on them will open the default browser and to show the terms.
Merge pull request #178 from flerda/terms

Show terms and conditions with shared decks.
Remove unused mindprod package and classes.

The BigDate class was used in methods in Utils.java, but those methods were never actually used anywhere in the application.
Merge pull request #179 from flerda/tabs

Delete unused layouts and classes.
Merge pull request #180 from hssm/mindprod-remove

Remove unused mindprod package and classes.
Bumped version 2.1alpha5
Merge pull request #171 from pabloem/iss1504-card-answer-revealed-early

Iss1504 card answer revealed early
Merge pull request #174 from pabloem/iss1400-deck-selection-card-editor

Issue 1400- Removing the line that was resetting the Current deck: field in the
Bumped version to 2.1alpha6
Squashed commit of the following:

commit 8c0b969b151993fbc328f3a0abe208dc156b4940
Author: tim.home <timothy.rae@gmail.com>
Date:   Wed Feb 19 11:48:25 2014 +0900

    Fixed the bug where preview button is shown from Add Note. Also added @JavascriptInterface decorator for Android 4.2+ compatibility

commit 56e378bc7b377ded1f6ec8b3b0c1c223b193f645
Author: tim.home <timothy.rae@gmail.com>
Date:   Tue Feb 18 14:16:19 2014 +0900

    Add missing code from JoltaTech

commit 0f611ce23fa6faa87ca866b55322168fc80c1810
Author: tim.home <timothy.rae@gmail.com>
Date:   Tue Feb 18 12:52:10 2014 +0900

    Extracted work from JoltaTech to add preview button to CardEditor.java and create PreviewClass.java, and manually brought it into the latest 2.1-dev branch.
Adding a tag-selection dialog on the custom study options dialogs