Improvements to Hash::expand and Hash::merge.

Because of the recursion in these functions, processing very large
arrays would take a very long time. I rewrote the functions to
eliminate any unnecessary recursion and function calls. Large arrays
are now processed much faster.
Fixed coding standard violations.
Merge pull request #4787 from hperrin/master_hash_improvements

Improvements to Hash::expand and Hash::merge. (master)
add test to prove requesthandler works correct with Angular wonky accept headers
Merge pull request #4798 from ceeram/2-angular

add test to prove requesthandler works correct with Angular wonky accept...
Revert "add test to prove requesthandler works correct with Angular wonky accept headers"

This reverts commit 8507ef83f175bbf3f6532dc68b6051f0d41acd82.

Incorrect header was used for this test, Cake cannot safely determine correct header.
To get CakePHP to respond with json, you can modify the angular common headers.
Merge pull request #4801 from ceeram/2-accept-revert

Revert "add test to prove requesthandler works correct with Angular wonk...
Update version number to 2.5.5
Fix small typo
Merge pull request #4842 from suzuki86/fix-typo

Fix small typo
Fix missing 'r' from your
Merge pull request #4843 from bcrowe/fix-typos

Fix missing 'r' from your
Added code consistency badge from phpcs
Added HTTP to URL
Make CakeSession::read() return null for all failure cases.
Merge pull request #4850 from ADmad/issue-4849

Make CakeSession::read() return null for all failure cases.
Merge pull request #4847 from ravage84/patch-1

Added code consistency badge from phpcs
Add test for find() and array conditions.

Add a test for conditions using an array with only one element.

Closes #4848
Fix Model::isUnique() not working as a validator.

While it *did* work for single fields, isUnique could not be used to
validate the uniqueness across multiple fields as documented. Because
validation methods pass arguments in an order the validator did not
expect the validation method would not work correctly.

Fixes #4571
Merge pull request #4851 from cakephp/issue-4571

Fix Model::isUnique() not working as a validator.