Add prototype pie charts for route/mode aggregations

TODO: Test system-wide data
TODO: Alternate chart types
TODO: Per-chart config?
TODO: Display route type name instead of int
Tweaks to enable multiple city display
Fix units and aggregation of length calculator

The units were in meters when kilometers were desired.
Also, the the mode aggregation was using an average when
it should have been using a sum.

Note: these number are now in the ballpark with reality,
but still don't look perfect. SEPTA rail is showing 551
kilometers, where it should be somewhere around 450.
Adding an issue to address this.
Merge pull request #152 from WorldBank-Transport/feature/fix-length-units

Fix units and aggregation of length calculator
Add mode/system geom string generation;Refactor
Manual merge on tests
Merge pull request #146 from WorldBank-Transport/feature/prototype-indicator-charts

Feature/prototype indicator charts
Replace cityname in indicator id with loop index

Cannot use cityname as those can have spaces/punctuation/etc
that tanks the id selector
Default Indicator.city_name to a string value

...so that we get a display name in the UI.

TODO: Attach a user-customized city_name to the
GTFSFeed object.
Add bulk indicator delete, filtered on fields
Complete Add/Remove City Modal

TODO: Copy translations
TODO: Scenarios

Updates angular translation files