Specify data dictionary name in lieu of full path to XML

[salsferrazza]

Instead of requiring the full path of the data dictionary to be specified at runtime, allow user to simply specify the dictionary name (such as FIX44 or FIX50SP2, then manufacture the full path of dictionary file internally before fetching. If the parameter includes the characters / or ., assume that the input is indeed a path and read that instead, vs. manufacturing the path.