Moved previously local to pin.cpp gpio control singleton object to its own module so it may be accessed from elsewhere
Added gpio_ctrl.cpp to library build Makefile
Refactored to use external gpio_ctrl and to use C++11 std::chrono and std::this_thread time and sleep functionality
Deleted implicit copy and move constructors and assignment operators from pin_base
Refactored pin_edge_event, supporting internal sys fs support to allow only constrution from ipin objects, only one pin_edge_event per GPIO pin, simplified sys fs supporting functions, removed redundant exception type and delete pin_edge_event move construstor and assignment operator.