IEC: handshake LISTEN/TALK only if it's for us

This enables checking if a device is present
and makes drive toggle with JiffyDOS / Ctrl-D work.
Fixes #56
Fix XS-1541 / 3.1541 firmware update scripts
Merge pull request #122 from Edilbert/master

Add commands FS_COPY, FS_DUPLICATE and FS_INITIALIZE
Merge pull request #123 from Edilbert/master

rename "errno_t" to "cbm_errno_t" in order to avoid name conflicts
Merge pull request #125 from Edilbert/master

Initialize local variables which cause clang warning messages if not ini...
Merge pull request #127 from Edilbert/master

Firmware parser enhancement for COPY/MERGE
Fix forgotten version update
Use stdbool.h
Rework NV storage

Separates IEC/IEEE-488 settings which fixes #19.
Stores common settings (not bus dependent) as well.
Platform specific code reduced to functions for reading/writing bytes.
NV settings stable across different compiler/versions as the NV storage
locations are no longer generated by the compiler but by the code itself.
Unfortunately, this instability prevents an automatic conversion from
NV data stored in the old format into this new one.
Merge branch 'master' of https://github.com/fachat/XD2031
Fix broken Xiec / Xieee commands
Prevent splitting of System Info

to prevent it from appearing like this:

>>>: ### XS-1541/XD2031 v0.9.2 ###
>>>: CMD:'XU=9'
>>>: SETTING UNIT# TO 9 ON iec
>>>: CMD:'XU=9'
>>>: SETTING UNIT# TO 9 ON ieee
>>>: SETTING UNIT# TO 9 ON ieee
>>>: , 14745 kHz
>>>:
>>>: Fuses: l=FF h=D4 e=FC l=FF
>>>
Revert "Prevent splitting of System Info"

which made the system info disappear

This reverts commit f048a32f9e53598c5a2615a7f140e6337707ddb1.
Add config.h / DEV_ADDR for XS-1541 / 3.1541
Remove a double declaration
Fix classic_match()

"?" matched against an empty string, what it should not do.

As a result of the fix, the variables used for name and pattern
are not interchangeable any more, which reflects in changed
variable names.
Fix broken test for cmdnames.c
Use stdbool.h
Re-create lost "make doc" for firmware's doxygen docs
Add imgtool to main Makefile and win32 distribution zip