Improves route preview landscape layout

[ecgreb]

Improves route preview layout in landscape mode.

• Introduces modified route preview layout in landscape mode with smaller text and margins to show more of the map.
• Moves distance and time onto either side of route mode widget in landscape mode.
• Does not show "Try a different mode?" text in landscape mode when no route is found.
• Adds null checks for layout components that only exist in portrait or landscape.
• Breaks down route preview layout code into smaller re-usable chunks.
• Extracts more values into dimens.xml to vary portrait vs. landscape.
• Fixes issue where compass and find me button were overlapping in landscape mode.

Closes #764

[souperneon]

Looks good @sarahlensing @ecgreb My only comment would be, separating distance and time makes it harder for the user - they have to look left and right before picking a mode. Don't have a more elegant solution off the top of my head that would be an easy fix. Wondering if others feel he same?

[ecgreb]

@souperneon I agree but also couldn't think of a better option that still conserves vertical space. Maybe lets go with this for now and revisit in the next release?