Reuse WP_Stream_Settings::get_active_connectors()
Include connector class checking

Before adding & registering a connector, check if the connector's class
is a subclass of WP_Stream_Connector
Introduce WP_Stream_Connectors::admin_notices()

The new method is added to the admin_notices hook by load() and will
print messages stored in $admin_notices
Fix connector labels storing
Prefix global var to avoid collision with others' code #277
Break of the loop instead of terminating the function #277
To allow logging of reordering actions
Fix sidebar name logged in reorder operations #277
Used to reference the last sidebar available, not the changed one
[CS] Drop one-liner conditional
Proper `default` detection in wp_stream_filter_input

Resolves #280
Merge pull request #265 from x-team/refactor-WP_Stream_Connectors

Refactor WP_Stream_Connectors
Merge pull request #281 from x-team/issue-280

Proper `default` detection in wp_stream_filter_input
Release notes for 1.2.4
Version bump to 1.2.4
Merge pull request #279 from x-team/issue-277

Fix widget reorder action logs
Merge branch 'develop' of https://github.com/x-team/wp-stream

Conflicts:
	includes/connectors.php
Fix issue after merging develop branch occure due to connector refactor  #251 #278