Changes for liblsl 1.14

change: CMake doesn't set CMAKE_INSTALL_PREFIXand CMAKE_BUILD_TYPE by default unless LSL_COMFY_DEFAULTS is set (Tristan Stenner)
change: liblsl requires a compiler with C++11 support, MSVC 2015 on Windows
fix: prevent race condition when two threads modify an overflowing buffer (#71, Jérémy Frey)
fix: improve latency and CPU usage (#71, Jérémy Frey)
fix: various build system fixes and improvements (Chadwick Boulay, Tristan Stenner)
added: enumerate network interfaces on startup, for now unused. Requires Android SDK >=26 (Tristan Stenner)
added: lsl_inlet_flush() to drop all outstanding samples from an inlet to avoid the pull_ overhead in realtime applications (Tristan Stenner)
change: the binary names are changed so that the OS resolver (e.g. find_library(lsl)) searches
for the correct library. Windows: liblsl32.dll / liblsl64.dll -> lsl.dll, Unix: liblsl.so. (Tristan Stenner)
change: the lsl_c.h header is now split into several header files (Tristan Stenner)
change: refactor logging, add log.file config option (Tristan Stenner)
change: replace various Boost libraries with C++11 counterparts (Tristan Stenner)

Provide feedback