devtools: sending missing messages to fix add/remove breakpoint

- 'Runtime.executionContextCreated' invoked after we supply the resource tree
- 'Debugger.scriptParsed' invoked for every script for which we supply resource content
- these may move to different places in the future and be invoked at different stages, but for now this suffices to make the breakpoint API work
docs: debugging debugium
tests: disabling travis for now

- updating the tests while in spike mode is not efficient
- most of the current tests are invalid by now
- once things are working properly we'll add tests back in (integration and tests for each agent)