Gracefully handle invalid chunks in HttpSocket

When invalid chunks are detected we should assume the server is
incorrect and handle the remaining content as a single large chunk.

Refs #5140
Bugfix for: Memcached Engine segfaults with memcached client version < 2.0.0

Fixes #5028
Merge pull request #5204 from tersmitten/memcached-engine-segfaults-with-memcached-client-version-200

Bugfix for: Memcached Engine segfaults with memcached client version < 2.0.0
Merge pull request #5196 from cakephp/issue-5140

Gracefully handle invalid chunks in HttpSocket
Fix mistake with previous commit.

I forgot to put the correct variable into the query like a doofus.

Refs #4168
Fix file_map being regenerated on every request.

A mistake a few months ago caused the file_map to always be regenerated
as Configure::write() would cause both Configure and Hash to be loaded,
invalidating the file map. By entering bootstrap mode earlier we can
avoid that.

Refs #5229
Merge pull request #5239 from cakephp/issue-5229

Fix file_map being regenerated on every request.
PHPUnit can be included as a phar file.

No need to install phpunit in order to run unit tests.  Simply place
'phpunit.phar' in the vendors folder.
remove space
Merge pull request #5248 from larryb82/phpunit_as_phar

PHPUnit can be included as a phar file.
Make the version option function as intended.

The version option is documented but does not work. While this 'breaks'
behavior, it also fixes what I think is a more important issue.

Refs #5234
Merge pull request #5253 from cakephp/issue-5234

Make the version option function as intended.