• Added fixes for MSVC 2017 and Boost 1.66.0
• Modernized cmake scripts (cmake 3.0 style)
• Added proper cmake targets - cppnetlib::cppnetlib, cppnetlib::uri, etc.
  These targets keep usage requirements like flags, definitions, include directories, a library location and library dependences.

With these targets you can replace the following cmake script:

target_include_directories(MyTarget ${CPPNETLIB_INCLUDE_DIRS})
target_link_libraries(MyTarget ${CPPNETLIB_LIBRARIES})
target_compile_definitions(MyTarget BOOST_NETWORK_ENABLE_HTTPS)

with

target_link_libraries(MyTarget cppnetlib::uri)