adding transparent background support to barcode
removing alpha as it's not used
#5465 use strlen instead of empty
#5465 unit test
#5465 added link to github issue
[http] Fix a couple of tests
[http] Enable online tests in Travis-CI
[http] More fixes
Fixes #5516
- adds fix into Zend\Mvc\Router\Http\Segment::encode
- adds test case for new fix
Fixes #5516
- fixes cs in test case
Added empty string option for session_cache_limiter as mentionned in the php manual: "Setting the cache limiter to '' will turn off automatic sending of cache headers entirely."
Giving more namespaces to FlashMessager

This change was made by another user and excluded after for some reason. Just putting it back
Added a test to show the duplication of routes when using a chain_link and the scheme route type.
update userguide manual link
Change hardcoded events names by its constant.
replaced array_key_exists to isset for performance
removed & in  since its failing test
add some unit test verifying nulls as array key or if its array values
added test to cover if second array arg has null value
fix strange exception message