Added new SmartPort Harddisk Controller (HDC) firmware for Enhanced //e. (@burniouf)
. remove the old DOSMaster entrypoints.
. firmware ID byte (at $FE) defaults to 4 ProDOS block devices (was 2 with older v2 f/w).
Enhanced //e defaults to using SP f/w, and older Apple II's still use the older v2 f/w.
Support up to 8 units per HDC (currently limited to 4GiB capacity for each unit).
Save-state: save HDC firmware in state file.
New slot-specific switches to configure each HDC's firmware: -s<N> -hdc-[sp|bm2|bm4].
New switch to select old non-SP firmware for all HDCs: -hdc-firmware-v2.
* New command line option to force a size for autoexpanding use.
* New HDD Controller firmware uses a separate v2 name and folder.
* Harddisk.cpp now loads HDD Controller firmware v2 by default.
* Save-state for 'Generic HDD' bumped to v4
