Update stable devtools protocol to v1.2

[paulirish]

Talked this over with dgozman and we agree on this basic approach:

• use current day copy of the protocol
• filter out everything that's experimental or deprecated (incl domains)
• ship as 1.2 (stable)
• remove 1.1

[auchenberg]

Does this mean CDP 1.2 has been finalized as of today?

[paulirish]

yup