Add elevation info

[Beck-berry]

I added the elevation info, it is displayed on the side panel after a search was made. It can be a negative number if the elevation of the start is bigger than at the end of the route.

Screenshots

  

Closes #38

[Beck-berry]

@tsobuskerudbyen What do you think about the icon?

[leonardehrenfried]

Sorry for the very late reply, but I think @tsobuskerudbyen was more looking for an elevation profile. Something like this:

Am I right @tsobuskerudbyen ?

[tsobuskerudbyen]

Yes, you are right @leonardehrenfried. (Shortly in from summer holidays here.)

[Beck-berry]

Then I'll close this PR and move #38 to the ToDo column. I'll have to rethink my approach.

[Beck-berry]

@leonardehrenfried Please check this, we discussed that this can be a base for #68. After that I'll add the graphical solution.