Support variadic function
Merged
change Value uintptr_t into class
Change method name mixed case into lower case
Merge header files
Remove object directory

--HG--
rename : src/vm/object/array.cc => src/vm/array.cc
rename : src/vm/object/function.cc => src/vm/function.cc
rename : src/vm/object/hashtable.cc => src/vm/hashtable.cc
rename : src/vm/object/imstring.cc => src/vm/imstring.cc
rename : src/vm/object/object.cc => src/vm/object.cc
rename : src/vm/object/record.cc => src/vm/record.cc
Start to split Symbol and String

--HG--
rename : src/vm/imstring.cc => src/vm/symbol.cc
Add string bytecode file format
Add string format to assembler
Eliminate unnecessary macros
Separate string and symbol
Fix symbol provider method name
Implement string/symbol conversion
Add FunctionInfo class
Introduce FunctionInfo
Refactor
Make <Class>.get_klass() be not self
Refactor
Refactor builtin objects
Eliminate needless using namespace and change vm method name