Remove unpadding of binary fields in FSDMsg.pack method

Content of binary of field must not be treated as ascii and unpadded. https://github.com/demsey/jPOS/commit/feb074238b871fc58007670871109f34b33afa32 remove call of ISOUtil.blankUnPad() for that fields.
And also additional jUnit test for ensure correct packing numeric,
ascii and binary fields with or without padding

Second patch https://github.com/demsey/jPOS/commit/7ce9ec9c109ae33ca55c248c78e434f306c185ea is a refactoring of FSDMsg for simplification

Refactor Iterators-while to for-each, replace StringBuffer witch StringBuilder.
if and throw - use of guard code pattern. Remove nonexistend Exceptions
from javadoc