This commit fixes 2 issues specific to the firefox version of the
extension:
First issue concerns the computation the position of the
border between the subwindows of the components tab which could go
terribly wrong due to the fact that the innerwidth of the window is
implicitly set to 10 when the owl devtools window is hidden.
Second issue comes from changes in the runtime.onMessage method of
browser which now requires to directly return the response instead of
using the sendResponse method.
Also perform a little cleanup on usage of browserInstance and in the
manifest.
This commit adds the code of the owl devtools extension.
This extension can be added on chrome or on firefox for
developpers to be able to inspect the contents of all owl
applications that are present on any web page, see all the
components, interract with them and their content to some
extend and perform a bit of profiling with their renders.
Julien Carion (juca)