Add a HTML page to / with Flowhub live url link
Make it clear Heroku envvars are optional
app.json: Fix spaces in hostname
app.json: Remove optional envvars

Optional annotations broke it, and confusing without
them so just leave it documented in README
Fix Flowhub URL from https
Protocol: Implement network:getstatus, more info on started/stopped
imgflo-runtime: Add --graph option for default graph

Also pass this with runtime:getruntime response.
Right now this is only way live-mode will work in Flowhub,
due to noflo/noflo-ui#389
Protocol: Start implementing :getsource for Graph instances

Don't like that component:getsource is used instead of graph:foo messages
for the initial/default graph, but it is the way Flowhub works right now...
Heroku: Default to loading a graph

That way should get working example up in Flowhub
Protocol: Also send connections for initial graph
Only print IIP line on success
graph_list_nodes: Fix internal data beeing freed by caller
Fix preview invalidations for default graph and live mode
Graph: Implement IIPs also for component:getsource

GeglColors are currently just showing "object"
json_from_gvalue: Support GeglColor
json_stringify: Move into utils.c file
Graph: Only save/send non-default IIPs

Partially as a workaround to noflo/noflo-ui#391
gvalue_from_string: Split out from set_property()
Implement string IIP -> integer conversion

Fixes unable to set integer properties when hitting noflo/noflo-ui#391
Remove debug print