Thread group#590

Merged

deanberris merged 3 commits intocpp-netlib:masterfrom

glynos:thread_group

Jan 31, 2016

Commits on Jan 30, 2016

Added a C++11 enabled thread_group (cf. boost's thread_group).
glynos
committed
Removed dependency on boost thread, including for examples.
glynos
committed
Removed depenency on boost program_options (replaced with cxxopts, which only depends on C++11).
glynos
committed