ADD initial README for plugin module
UPD changing plugin README to remove references to erroneous interface
ADD Manager and PluginSignature interfaces
ADD initial test for checking getting empty regisetered plugins
ADD very simple implementation to handle the getters in Plugin\PluginSignature
ADD initial FirePlugin\Manager to get tests running
UPD adding assertion for empty array to first FirePlugin\Manager test
UPD fixing PHPdoc tags and adding docblock to first test
UPD adding property to store registered plugins and pass first test
UPD changing so that return method does not necessarily have to be boolean
UPD adding test for FirePlugin\Manager storing registered plugins properly
UPD adding appropriate doc param, storing plugins that are registered
UPD adding test to ensure that plugins get autoloaded
UPD adding test to ensure only Callbacks are attempted to be added to Mediator
UPD adding code to throw exception for invalid callbacks
UPD adding test to ensure that plugin callbacks are added to mediator
UPD adding code to add callbacks to Mediator
UPD adding test to ensure that plugins from an array can be added
UPD adding comments explaining why test is only checking one aspect of registration
UPD fixing some docs, cleaning up exception message, adding code for multiple plugin registering