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
Use name() instead of hand quoting sequence names.

By using name() we can easily accomodate postgres sequences that exist
out side of sequences.

Fixes #4168
Prevent zero only lines from being emptied
Merge pull request #5202 from ndm2/email-zero-only-lines-fix

Prevent zero only lines from being emptied
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
Bump version number to 2.7.0-dev

Open a branch for any development on 2.7.x which will be a 2.x API
compatible release.
Add test for css() and script() with the same resource identifier
BC fix for css() and script() with identical resource names
Merge pull request #5205 from rchavik/2.6-fix-html-helper-regression

2.6 Fix html helper regression
Refactoring the detector code for CakeRequest::is() and adding default detectors for JSON and XML.
Adding a test for the refactored CakeRequest code.
phpcs fixes in Cake/Network/CakeRequest.php
phpcs fix in Cake/Test/Case/Network/CakeRequestTest.php
Enable sslmode for PostgreSQL connections

By default, PHP 5.5 and PostgreSQL PDO will not allow SSL connections. This adds the default of "allow", but also the user may override the setting to "require" or any of the other potential values. 

See: http://php.net/manual/en/function.pg-connect.php
Update database.php.default to include sslmode
Add sslmode support for postgres.

While 2.6 is in RC this pull request was open well before that, and
I simply forgot to merge it in.

Refs #5173
Restructuring the CakeRequest::is() code and related code a little.