Use tidy to fix deprecated keyword: Wait Until Network Is Idle to Wait For Load State

[aaltat]

Is your feature request related to a problem? Please describe.
Use tidy to fix deprecated keyword: Wait Until Network Is Idle to Wait For Load State

Describe the solution you'd like
Add command to rfbrowser which will run custom transformer Browser library.

rfbrowser transform --wait_until_network_is_idle -path path/to/tests

transform is telling that we are fixing deprecated keyword, --wait_until_network_is_idle will tell which keyword we are fixing (Wait Until Network Is Idle) and --path will define where command is looking tests. Command should run only our converter and it should disable all other tidy converters.