Modernize codebase

- Enhance CMakeLists.txt files.
- Move to Boost Test from Google Test to support pre-C++11 compilers.
- Add more configurations on CI matrix builds.
- Other minor fixes

example/cpp11/CMakeLists.txt

@@ -1,8 +1,4 @@
-IF (MSGPACK_CXX11 OR MSGPACK_CXX17)
-    INCLUDE_DIRECTORIES (
-        ../include
-    )
-
+IF (MSGPACK_CXX11 OR MSGPACK_CXX14 OR MSGPACK_CXX17)
     LIST (APPEND exec_PROGRAMS
         container.cpp
         non_def_con_class.cpp
@@ -20,9 +16,8 @@ IF (MSGPACK_CXX11 OR MSGPACK_CXX17)
             ${source_file_we}
             ${source_file}
         )
-        TARGET_INCLUDE_DIRECTORIES (${source_file_we}
-            PRIVATE
-                $<TARGET_PROPERTY:msgpackcxx,INTERFACE_INCLUDE_DIRECTORIES>
+        TARGET_LINK_LIBRARIES (${source_file_we} PRIVATE
+            msgpackc-cxx
         )
         IF ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
             SET_PROPERTY (TARGET ${source_file_we} APPEND_STRING PROPERTY COMPILE_FLAGS " -Wall -Wextra")