Add PHP 5.6 to travis-ci and remove .gitattributes from export

Signed-off-by: crynobone <crynobone@gmail.com>
Fixes testcase namespace.

Signed-off-by: crynobone <crynobone@gmail.com>
Move to PSR-4.

Signed-off-by: crynobone <crynobone@gmail.com>
Release v2.1.2

Signed-off-by: crynobone <crynobone@gmail.com>
Merge branch '2.1'

Signed-off-by: crynobone <crynobone@gmail.com>

Conflicts:
	src/Html/Abstractable/Environment.php
	src/Html/Form/Environment.php
	src/Html/Table/Environment.php
	src/Orchestra/Html/Abstractable/Environment.php
	src/Orchestra/Html/Abstractable/Factory.php
	src/Orchestra/Html/Form/Environment.php
	src/Orchestra/Html/Form/Factory.php
	src/Orchestra/Html/Table/Environment.php
	src/Orchestra/Html/Table/Factory.php