Fixes #14934 - Remove rails 3.2 workaround from parameter model

fixes #13244 - update Rails to 4.2.6

- Add responders gem to support class-level respond_to usage
- http://edgeguides.rubyonrails.org/4_2_release_notes.html#respond-with-class-level-respond-to
- Replace foreigner with native Rails 4.2 FK support
- uses a patch from Rails 5 to support Foreigner's...

refs #14691 - user editing self should not change User.current

Rather than changing the behaviour of #to_label to return persisted
data, the User.current object should not be modified with unsaved data
from the form submission or API update.

User.current is used for authz as well as for display purposes, so...

fixes #14502 - fix documentation of the hosts controller for puppetclass_ids

previously it wrongly stated that the parameter is called
puppet_class_ids

Fixes #14503 - don't join reports with the logs and resources explicitly in API

Using `.includes(:logs => [:message, :source])` in the search scope
for reports caused serious performance issues (ending up with server
taking all of its memory). I've found no reason for the `includes` to...

Fixes #14330 - Provide option in hammer to change display type for
libvirt compute resource

Fixes #5816 - allow editing and displaying self via API

fixes #12746 - list compute resources from plugin definitions

Load the full list of known CRs from plugins on the fly, instead of
modifying the class-level list of supported plugins. Since plugin
definitions don't get reloaded, this allows the ComputeResource class to...

fixes #14050 - resolving N+1 query on hosts#index

Fixes #14264 - improve primary interface selection