update gamma api

update api and http doc

Merge pull request #77 from milliyang/master

[VISCA] update wb; R/G/B/ Offset

Update http.md

Update freed.md

[VISCA] update x24 zoom code mapping

[FreeD] update doc and sample receiver

Merge pull request #70 from triccyx/patch-1

update js api link

add freed protocol doc

add visca spec

update readme href-link

update http.md

update http, provide js api