Jason L. Shiffer

Results 2 issues of Jason L. Shiffer

Adds: - SetAsDefaultProtocolClient - RemoveAsDefaultProtocolClient - IsDefaultProtocolClient Corresponds to PR [protocol-client](https://github.com/asticode/astilectron/pull/60) in astilectron

Add: - setAsDefaultProtocolClient - removeAsDefaultProtocolClient - isDefaultProtocolClient - open-url app event Matches go-astilectron PR [protocol-client](https://github.com/asticode/go-astilectron/pull/368) and issue #57.