Added new brands and models :)

[gtjadsonsantos]

Elgin

Code	Supported Models	Controller
2801	HVQI12B2FB	Broadlink

Gree

Code	Supported Models	Controller
3182	GWH18ACD-D3DNA 1M	Broadlink
3183	Unknown model	Broadlink

Agratto

Code	Supported Models	Controller
3000	ECST12FR4-02 ECST19QFIR4-02	Broadlink

[vassilis-panos]

Hi and thanks for the hard work.
Please raname Agratto from 3000 to 2980 and I also believe that precision should be 0.5.