Rescue subclasses in error middleware.
Fix typo in rescue_from unit test (Communication --> Communications).
Merge pull request #546 from xevix/fix_rescue_from_unit_test

Fix typo in rescue_from unit test (Communication --> Communications).
Rename children --> subclasses to match the name used in the code.
Remove unnecessary test case.
Address #543 - raise proper validation errors on array/hash types

 * Also adds a :type option to group/requires/optional with block,
   which can either be Array or Hash. It defaults to Array.

 * Fixes (2) and (3) as mentioned in #543

 * There is a quirk around query parameters: an empty array should
   pass validation if the array itself is required, but with how
   query parameters work, it doesn't. It does work fine with body
   parameters using JSON or similar, which do have a concept of an
   empty array.
README.md and UPGRADE.md update for #543, #545
Merge pull request #547 from bwalex/nested_vals_readmes

README.md and UPGRADE.md update for #543, #545
Updated/renamed UPGRADING.
Define errors in context/before blocks.
Rename exception classes to match README.
Merge pull request #548 from xevix/rescue_from_tests_use_different_exception_names

rescue_from tests now use different exception names
Fix for #464: gracefully handle invalid version headers

 * Catch the exception(s) thrown by rack-accept and return a 406 if one
   is caught.

 * Add a spec to cover this case.
Added ability to restrict declared(params) to the local endpoint with include_parent_namespaces: false.
Merge pull request #549 from bwalex/fix_for_464

Fix for #464: gracefully handle invalid version headers
add posibility to define reusable named params
Merge pull request #550 from dm1try/named_params

Add possibility to define reusable params.
Fixed typo in README.md
Merge pull request #555 from ujjwalt/patch-1

Fixed typo in README.md
Fix: object_fields should be params.