Add support for missingValueCode in EML parser
Currently, EML parser doesn't handle missingValueCode. We should replace the
missingValueCode by NULL in the data file.
#4 Updated by Jing Tao about 15 years ago
EML parser now can stored missingValue. According Ptolemy adding NULL Token
connecpt, Kepler will transfer the missing value to NULL Token. The null tokens
now we can handle include int, long, double and string. Since Ptolemy haven't
finailized the NULL token yet, kepler will keep changeing too.