Auto-apply fixes using bazel-watcher protocol

[alexeagle]

https://github.com/bazelbuild/bazel-watcher#output-runner

iBazel is capable of producing and running commands from the output of Bazel commands. If iBazel is run with the flag --run_output then it will check for a %WORKSPACE%/.bazel_fix_commands.json and if present run any commands that match the provided regular expressions.

We should support the same thing, so that if a user has already setup ibazel run to auto-repair certain problems, aspect run does the same.