Support Gyazo ID

Refs:

- Darwin: https://github.com/gyazo/Gyazo/blob/master/Gyazo/script
- Linux: https://github.com/gyazo/Gyazo-for-Linux/blob/master/src/gyazo.rb
- Windows: https://github.com/gyazo/Gyazowin/blob/master/gyazowin/gyazowin.cpp