jPOS-112 Remove unpadding of binary fields in FSDMsg.pack method

Content of binary of field must not be treated as ascii and
unpadded. Remove call of ISOUtil.blankUnPad() for that fields
Created additional jUnit test for ensure correct packing numeric,
ascii and binary fields with or without padding.

Signed-off-by: Robert Demski <drdemsey@gmail.com>
jPOS-112 Refactoring 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

Signed-off-by: Robert Demski <drdemsey@gmail.com>