Local GPX file support, first push towards multilayer support.
Optimize road category for 3 column layout
minor style tweak
updating mockups.
Merge branch 'master' into layers
stop adding extra line break when building locales.js

fixes #1090
Re-add area as a geometry for tagless other preset

Without it, areas without area=yes don't match any preset
fix #1087
adding delete back into tag editor, closes #1088
hide preset descriptions when updating grid
adding more line presets.
more line icons.
adding more line presets, resizing them.
move preset icon and type name into header
Remove name seperator in editor
Add ref field to highways
Refactoring and fixing layers

* Fixed opacity control
* Reorganize layer switcher
* Add GPX item to menu
* Allow user to cinch to GPX extent

Needs:

* Moderate refactoring
* Possibly a specific 'layerchange event'
* Dropping GPX on the map should be a behavior, probably, instead of in
  the layer
* Layers, if we want them, should be named rather than just have list
  indices
* A better icon for zoom to extent and for that icon to be properly
  placed
Fix tests
Merge branch 'master' into layers
Detect file and drag and drop support
Merge pull request #1093 from systemed/layers

Layers