Add base menu for plugins
Improve dialog for configuration

Add base model for plugins
Parse list of plugins and show menu
Normalize dialog to edit json
Add actions menu for each plugins
Add remove and configuration for plugins
Update plugins list and manually editing book.json
Write package.json according to plugins list
Add action to add a plugin
Remove old plugins from package.json
Complete action to install dependencies using npm
Merge pull request #133 from GitbookIO/feature/plugins

Plugins Manager