DI MarkdownInterface at plugin repositories
Change PluginRepository to not Singleton class
Modify test
Change HaikMarkdown.

Add registerPluginRegister and other methods.
Delete setPluginRegister.
Delete PluginRepository Class
Modify Plugin.

Require MarkdownInterface at Plugin::__construct.
Pass MarkdownInterface instance from AbstractPluginRepository
Follow changes
Merge pull request #1 from toiee/di-markdown-interface

DI MarkdownInterface