HALO Style revamp

- speech bubbles are centered
- number batches are roundand simplified, same color as in g+
- markers appear as dots above the bubble
- hiding and dimissing triggers text hints
- couple of bugfixes

WARNING: some of the drawables are good for xhdpi only for now and must
be scaled down for the other resolutions

Change-Id: I503c14bc5253a6e6b10e0be92c057bea4d18c99a