Review custom WDA commands, add extension methods

[qmfrederik]

We should review all custom WDA commands (starting with /wda or /appium) and add support for them in Malaga.

They can be listed by reviewing the source -- say

• FBAlertViewCommands.m
• FBCustomCommands.m
• FBDebugCommands.m
• FBElementCommands.m
• FBFindElementCommands.m
• FBInspectorCommands.m
• FBOrientationCommands.m
• FBScreenshotCommands.m
• FBSessionCommands.m
  • POST:@"/wda/apps/launch"
  • POST:@"/wda/apps/terminate"
  • POST:@"/wda/apps/state"
• FBTouchActionCommands.m
• FBTouchIDCommands.m
• FBTouchIDCommands.m

[qmfrederik]

@bartsaintgermain :)