iBazel now watches the log warning from Bazel outputs. Users can watch for
specific commands and apply them automatically. The command matching is
implemented by regex and it is configurable.

Fixes: bazelbuild#18

iBazel currently only supports "run" for single target. Running multiple
targets requires separate Bazel command executions and busy waiting for
build processes.

Implement "mrun" command which takes in arbitrary number of targets, and
run all of them at once. We can pass in corresponding arguments with
prefix "--arg=".