Merge branch 'hotfix/15'

Close #15
[#3] Allow validating collections

- Added functionality to allow seeding the validator with a map or rest
  controllers -> route identifier names. This data is used to determine if the
  request represents a collection.
- If a request represents a collection, the discovered input filter is used to
  seed a CollectionInputFilter.
- Files are not merged with incoming data in the case of collections; too hard
  (impossible?) to match files to individual sets.
- PATCH requests do not use validation groups (since data may differ between
  sets).
[#3] Make PATCH to collections work like entities

- Created PatchCollectionInputFilter; isValid() method sets the validation group
  on the input filter for each iteration of a data set, raising an exception if
  an error occurs when adding the validation group.
- Altered ContentValidationListener to create either a
  PatchCollectionInputFilter or a CollectionInputFilter based on whether at
  PATCH or other style request is being made.
[#3] Allow POSTing collections

- Allows POSTing many entities at once, and properly validates them now.
  The REST service will need to detect if an array of data is present,
  or a single entity.
[#3] Fix factory

- As noted in a comment on the PR, `$allConfig` needs to be passed to
  `getRestServicesFromConfig()`, not `$config`.
[#3] better variable naming

- Suggested by @martinezdelariva
Merge branch 'hotfix/3' into develop

Forward port #3