flight.js: fix getNextSmallerIndex again.

This method doesn't do what it's said to do: it returns the next
smaller index to value in array but at least 0.
TravisCI: Added "redis" service to config file
assets: Use raw.github.com instead of rawgithub.com

rawgithub.com seems to do some strange gzip compression that webassets is not
able to handle. this commit can be reverted once rawgithub.com is fixed.
Revert "assets: Use raw.github.com instead of rawgithub.com"

This reverts commit faa3a3115fb2978625631e997b9bc195fe607d59.

rawgithub.com is fixed now
views/errors: Handle EOFErrors by returning RequestTimeout
ol-PlayButton.js: add touchend event to play button

The click event doesn't get fired on a ipad with safari, therefore
the touchend event handler.
ol-PlayButton.css: increase z-index above 1000

Show it above the usual map overlays but below the layer switcher.
templates/upload/result: use vertical tabs for flight list

Import bootstrap-vertical-tabs.css from
https://github.com/dbtek/bootstrap-vertical-tabs
with some minor modifications for small layouts.
templates/upload/result: show barogram of uploaded flights
baro.js: pass additional options to flot
Fork flot-selection plugin
Rename jquery.flot.selection.js to jquery.flot.flight-upload.js
jquery.flot.flight-upload.js: adjust coding style
jquery.flot.flight-upload.js: remove unnecessary y-range stuff
flight-upload.js: default selection color is dark gray
flight-upload.js: invert selection
flight-upload.js: every selection is sane.
flight-upload.js: change selection only when dragging the takeoff/landing markers
flight-upload.js: remove debugging code
flight-upload.js: change cursor style if cursor is over a marker