JS cleanup, dynamic datepickers, and slim filter queries

+ evaluate dynamically added datepickers (f.has_many form)
+ Filter form: don't pollute the URL bar with empty input values
+ Clear Filters button: remove return value (it's never reached)
#1920 - Download links option supports an array of formats to customize resource listings
get Travis CI working

## Changes

### Misc
- reordered Gemfile -- shouldn't change functionality
- fix test env builder to support Rails versions properly

### Issues
- #1966
  - fix missing `decorator_method` for Draper
- #1967
  - remove 1.9 hash syntax
  - fix I18n dynamic re-translation feature

### Travis
- use latest Rails maintainence releases
- use latest Bundler version
- remove REE & 1.9.2
- add 2.0.0