Added POST request support to urlfetch
Added abort to urlfetch methods

In case of socket-only errors like timeout or connection refused
there is no HTTP answer from server. In such cases it's more
sutible to abort the request with error_code == errno.
Added urlfetch::post method to c++ stub
Added urlfetch::post method to c++ stub
Proper dependencies for URLFetch.
Merge branch 'v0.10'
Changelog bump.
Changelog bump.
Merge branch 'v0.10'
Drop cocaine::error_code.

Follow the changes in master.
Merge branch 'master' into ipvs