[windows][melodic] use c++11 std::snprintf

[seanyen]

This pull request is in favor of C++11 std::snprintf usage and to remove MSVC specific CRT functions _snprintf_s.

This change is motivated by a name conflicts against Boost. Beginning from Boost v1.69, a new addition system_category_win32.hpp is added to Boost.System, and in this header, it refers to std::snprintf in a code path. And because snprintf has been redefined as _snprintf_s in many places in ros_comm, it subsequently replaces std::snprintf with std::_snprintf_s and results in compiler errors.

[seanyen]

@mikepurvis This is ready for review too. The change basically is in favor of standard C++11 over MSVC specific APIs.

[mikepurvis]

Great, thanks! I'm assuming that since ROS 1 on Windows is all officially still at an experimental stage, there's minimal commitment to supporting older MSVCs where this might not work?