fix the efyj::write function

- Fix many error in XML format.
- Add unit test to read a wrote DEXi file.
  - Add a make_temporary function to write into temporary directory.
test: move EXAMPLES_DIR into unit test only

Use the CMake set_target_properties to assign EXAMPLES_DIR directory
instead of the global add_definition.
test: add load/save/load DEX file

This unit test in only available for GCC 4.9 and Clang.