Add basic details to addon-info.json
Add "name" to addon-info.json
Add addon-info.json for examples/helloworld/
Merge pull request #36 from google/addon_info_basic

Flesh out addon-info.json and add addon-info.json for helloworld
Merge pull request #39 from google/plugin_detect

Add detection for plugins manually added to runtimepath
Add tests for maktaba#plugin#Enter and fix bugs (ftplugin, error msg)
Merge pull request #41 from google/enter_bugs

Add tests for maktaba#plugin#Enter and fix bugs (ftplugin, error msg)
Add support for detecting unregistered plugins using #plugin#Detect()
Add Usage example to README