Fix bug #140

Allow #376 to process a httpCall for http extensions by not previously
setting firstTime true for 'w' block.
Added http success msg

http extensions cannot currently display a meaningful 'green dot' msg
such as 'WeDo connected' as the javascript extensions can. Therefore add
an http ext.success msg in an identical style to the existing 'yellow
dot' ext.failure msg.
Merge pull request #232 from cpseager/master

Fix bug #140