DSP-1228 related: improvement to error information
C++11 syntax
add zmqpp support for a socket 'label'
Merge branch 'develop' into feature/dsp_1228
Merge branch 'develop' into feature/dsp_1228

Conflicts:
	src/zmqpp/socket.hpp
use string in preference to char*

request from Ben
fixed stupid error
Merge pull request #4 from datasift/feature/dsp_1228

Feature/dsp 1228