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
Merge pull request #1970 from Daxter/bugfix/1927-travis-ci

[1927] Get Travis CI working
fix_duplicating_css_ids_bug: generate id with prefix
Limit the TableCheckboxToggler to 'top level' tables.
Merge pull request #1993 from fd/master

Limit the TableCheckboxToggler to 'top level' tables.
Fixed the batch actions drop down menu for nested tables
refactor
If nil return value, use the form buffer instead

closes #887
Merge pull request #1991 from joxxoxo/fix_duplicating_css_ids_bug

namespace hidden field IDs
refactor breadcrumb helper

+ ActiveRecord#find accepts a string (even when searching for a numeric ID)
+ removed unnecessary begin/rescue/end block; used nil-returning method alternatives
+ use `path` instead of `fullpath` to get rid of query parameters (we already leave them out)
Merge pull request #1938 from Daxter/refactor/breadcrumb-helper

Refactor breadcrumb helper
refactor applicaiton.rb
Merge pull request #1996 from Daxter/bugfix/887-form-buffers

[887] Respect the form buffer!
rollback shoulda-matchers
Merge pull request #2004 from Daxter/bugfix/rollback-mocha

Rollback mocha / shoulda-matchers
update all rails versions in the test suite

For #2005

This fixes a problem encountered by anyone who had generated their
`spec/rails` test environment (occurs on first run) after #1970 was
applied. The problem was that I had updated only a few places where we
refer to the current Rails version to be tested. This commit changes
all of them, as well as bumps 3.2 and 3.1 to reflect the new release.

If you ran into the #2005 problem, please run these steps:
```ruby
rm Gemfile.lock
bundle
rm -rf spec/rails/
rspec spec
```
consolidate Rails versions to the Travis config file

Now everything depends on `.travis.yml`. If that updates, so to does
the manually-run test suite.
Merge pull request #2006 from Daxter/bugfix/update-all-the-rails

[2005] Update all the Rails!
Merge pull request #2007 from fd/master

Position the dropdown menu relative to the next positioned parent instead of the document.
keep `remove_filter` from hitting the database

Now any calls to it are cached until render time :heart: