Final UI Tweaks

[hwray]

I'm going to use this issue to keep track of small UI tweaks I'm noticing in the final rounds of user testing before heading to the Play Store.

• After tapping to send a join jam request, users should receive persistent UI feedback as long as they're waiting for a response from the master. This could take the form of greying-out that Jam in the list, appending extra text, or adding some kind of spinner/waiting animation to that entry.
• Bottom margins on the Jam list view are inconsistent, because they're set to accommodate the progress bar on the Master phone, which is absent from the Client phones. Solution: Make the margin consistent between Master/Client by tweaking progress bar UI, or set the margin programmatically based on a Master/Client check.
• We need better visual distinction between songs/albums in the music browser view. We should definitely add some vertical spacing between different albums. I'm also going to experiment with adding a very thin border between each list item in the browser, as well as a subtle alternating coloration on the backgrounds like iTunes does.

[hwray]

• The background and text color of the Settings menu should match the rest of the app.
• Remove the custom back button from the Settings menu and make sure the stock Android back button properly redirects to either the main screen / Jam screen as appropriate.

[hwray]

• The "Added by" username on the Jam screen should be right-aligned with its parent.
• Text in the music browser list view should be properly truncated with "..." when too long
• The "Now Playing" text on the Jam screen should be removed and replaced with a non-text indicator (bright red background color and/or speaker icon).

[hwray]

• Change scroll bar color to match new tab underline color (red instead of blue)

[hwray]

• Keyboard should appear automatically when "Name Jam:" notification pops up.

[hwray]

I've got all these tweaks implemented except for the Settings screen background, because we don't actually even have a layout specified for that Activity, which warrants a separate issue.