ihex file transfer support #43

Classes added to parse ihex files (ExtendedSegmentAddress, StartSegmentAddress, and StartLinearAddress record handling still needs to be added, but these were record types not present in any of the available ihex test files).

The classes expose all details at the primitive level for customised handling of transfers.

The classes also provide wrappers for simpler transfers.

Use of the wrappers has also been embedded within the Uds object to support attachment of an ihex file and simple transfer calls.

The Uds file has had a final wrapper added to support transfer of a specified ihex file with a simple reqDownload, transData and transExit combination.

Most of the options have been tested to some extent or other either informally or via the transData unit tests.

Merged to master after review with Richard.