build: CMake refactoring

Includes:
- refactor build_lib and build_lib_example macros
    - unify src and contrib macros
    - replace macro with function not to leak definitions
    - parse list of arguments
- different cmake-format file for modules to list one item per line

src/openflow/examples/CMakeLists.txt

@@ -1,9 +1,9 @@
-set(name openflow-switch)
-set(source_files ${name}.cc)
-set(header_files)
-set(libraries_to_link ${libopenflow} ${libinternet} ${libcsma}
-                      ${libapplications}
-)
 build_lib_example(
-  "${name}" "${source_files}" "${header_files}" "${libraries_to_link}"
+  NAME openflow-switch
+  SOURCE_FILES openflow-switch.cc
+  LIBRARIES_TO_LINK
+    ${libopenflow}
+    ${libinternet}
+    ${libcsma}
+    ${libapplications}
 )