upgrade some gems
Merge pull request #84 from it3s/update

upgrade some gems
fix the use of _.template

"Underscore templates no longer accept an initial data object. _.template
always returns a function now."
starting layers editor
save layers data
add colorPicker component
add colorPicker and tags widget to layers editor
refactor tags stylesheet
improve tags component
improve colorPicker component
add `$.setComponentValue([name], value)` function
improve layers editor
improve layers editor layout + fixes
add specs
remove unused files
fix layers editor issues
add `sortable` javascript component
save layer position
fix toggle button
apply css filter to map tiles