SDK ol3edit Styling Suggestions

@ahocevar 

List of suggestions in this PR:

- Moved feature table to side panel and for responsive bottom panel below map - map is resized accordingly when body tag is resized
- Moved navbar controls out of a dropdown and into a list so they're more easily accessed
- Made layer legend collapsible and moved to bottom right of the map
- Feature table is now a bootstrap table-responsive, in case attributes are too long to display in given space
- Error modal and turning off drawing in case of transaction errors
- Draw mode cursor and green button state

(Not the most compact code however.)