finished the implementation of string module
add eval module for klang
add some definition for global definition
add string pool module
finished the implementation of string pool module
add some interfaces for klang
add some interface for global definition
improved the definition of global
updated global
add eval module for klang language
updated the functional statement for Makefile
add some definitions for global definition
add some interfaces for eval module
add some functional interfaces for klang
finished the implementation of eval module
add execute module for klang