0.13.2

CMake now:

• Does not optimize away our entire library (no -fwhole-program when building libraries)
• Uses a linker version script on linux when building the watcher-c shared library
• Defaults to not build sanitizer and test targets
• Adds an RPATH to the library targets (i.e. watcher-c) when building for Apple targets
• Uses a more conventional BUILD_TESTING to control whether test targets are produced (instead of BUILD_TEST)

Various documentation improvements in the readme and CMake build file.