Remove .gitattributes from export

Signed-off-by: crynobone <crynobone@gmail.com>
Add PHP 5.6 to travis-ci

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

Signed-off-by: crynobone <crynobone@gmail.com>
Add support for Orchestra\Asset\Container::prefix() to support external URL. Closes #7.

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

Signed-off-by: crynobone <crynobone@gmail.com>
Release v2.1.1

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

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

Conflicts:
	src/Asset/Environment.php
	src/Orchestra/Asset/Environment.php
	src/Orchestra/Asset/Factory.php