Add unittests target to the binary distribution (issue #1632)

- Move all tests from the top-level directory to tests/.
- Move files shared by cefclient and unittests to tests/shared/.
- Add a fused (single header/source file) version of gtest in
  tests/gtest/ with associated CMake configuration.
- Test-only headers are now exposed in include/test/. Unit test
  targets must define UNIT_TEST in order to access them.
- Replace usage of USING_CEF_SHARED with WRAPPING_CEF_SHARED for
  clarity (only the libcef_dll_wrapper target should define it).
- Remove the RENAME_DIRECTORY CMake macro which is no longer used.
- Remove C++11 usage from unittests sources for compatibility with
  the binary distribution configuration.
- Windows: Fix build errors due to chrome_elf.dll and imm32.lib
  missing from the CMake configuration.

cmake/cef_macros.cmake.in

@@ -96,10 +96,12 @@ macro(SET_CEF_TARGET_OUT_DIR)
 endmacro()
 
 # Copy a list of files from one directory to another. Relative files paths are maintained.
+# The path component of the source |file_list| will be removed.
 macro(COPY_FILES target file_list source_dir target_dir)
   foreach(FILENAME ${file_list})
     set(source_file ${source_dir}/${FILENAME})
-    set(target_file ${target_dir}/${FILENAME})
+    get_filename_component(target_name ${FILENAME} NAME)
+    set(target_file ${target_dir}/${target_name})
     if(IS_DIRECTORY ${source_file})
       add_custom_command(
         TARGET ${target}
@@ -118,19 +120,6 @@ macro(COPY_FILES target file_list source_dir target_dir)
   endforeach()
 endmacro()
 
-# Rename a directory replacing the target if it already exists.
-macro(RENAME_DIRECTORY target source_dir target_dir)
-  add_custom_command(
-    TARGET ${target}
-    POST_BUILD
-    # Remove the target directory if it already exists.
-    COMMAND ${CMAKE_COMMAND} -E remove_directory "${target_dir}"
-    # Rename the source directory to target directory.
-    COMMAND ${CMAKE_COMMAND} -E rename "${source_dir}" "${target_dir}"
-    VERBATIM
-    )
-endmacro()
-
 
 #
 # Linux macros.