WORK IN PROGRESS: Feature tree (Result Panel)

Basic functionality is in place and it's integrated into the tools menu.

I put this up maine for @tonio to have a quick first look. Please see 6.2.14 in the specs for how it should look like. Feel free to change the html structure and css if you find the time. I would be interested to know if there is a possibility to have animated loading icons to replace existing text.

Code review not needed as of now.

Note: branch contains test-specific code that should not end up in master. This allows to checkout the branch and 
testing the feature directly. This changes consist of 1) having the right layers loaded at startup and b) having the right tools menu open.

Note: Backend will likely change in the future. We use identify (postgres DB) now which is _very_ slow on big bounding boxes. In the future it will be sphinxSearch backend.

`lang=en&topic=ech&bgLayer=ch.swisstopo.pixelkarte-farbe&X=151009.24&Y=630558.61&zoom=5` are resonably parameters for testing.