added response body to response object in onResourceReceived event

https://github.com/ariya/phantomjs/issues/10158
resource body is not converted to base64 anymore

https://github.com/ariya/phantomjs/issues/10158
fixed multiple onResourceReceived events for one real event

https://github.com/ariya/phantomjs/issues/10158
setting bodySize attribute of resource object on 'end' stage

https://github.com/ariya/phantomjs/issues/10158
Fixed body string initialization code (0 byte for empty strings)
Also fixed same code in filesystem module

https://github.com/ariya/phantomjs/issues/10158
Merge branch 'master' into resource_body
response body is only available in onResourceReceived event,
if url matches one of the patterns in 'page.captureContent' property

https://github.com/ariya/phantomjs/issues/10158
Merge remote-tracking branch 'dparshin/resource_body'