Various UI fixes

* Red/Blue dot in SeekBar for hot pot
* Indicate pot present
* Rename app
Add support for two temperature sensors

Also control based on temperature of the pot itself, not just the
contents temperature. This makes it possible to avoid the milk to
burn at the surface of the pot.
Fix clock press timing

If the user has pressed the clock we must wait for the hob to leave
the "clock mode" before trying to simulate presses otherwise we might
end up changing the time of the clock instead of the power level. This
almost worked, but did not take into consideration that the hob stays
in "clock mode" while adjusting the time. Solve this by only clearing
the "clock mode" once we have got ok to press a button.
Readme.md: Add link to gh-pages