Utilize data_get() and refactor some code to reduce complexity path.

Signed-off-by: crynobone <crynobone@gmail.com>
Update changelog for v2.1.5

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

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

Signed-off-by: crynobone <crynobone@gmail.com>
Merge branch '2.1' into 2.2

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

Conflicts:
	src/Html/HtmlServiceProvider.php
Merge branch '2.2'