Added descriptions for indicators
Changed "Rush" to "Peak"
Changed "Rush" to "Peak"
Changed "Rush" to "Peak"
Changed "Rush" to "Peak"
Extract translations for map indicator selection

Also changes the wording  from "Indicator Selection" to
"System/Scenario Selection", and removes the Indicator
Aggregation selection, since viewing by route is really
the only one a user would want to see.
Remove Chinese indicator descriptions
Remove ACCESS_INDEX
Fix affordability calculation description
Merge pull request #507 from WorldBank-Transport/feature/indicator-descriptions

Feature/indicator descriptions