serial-dmm: Implemented support for Voltcraft ME-42 (driver voltcraft-me42).
serial-dmm: Implemented support for Voltcraft M-3650CR (driver voltcraft-m3650cr).
hameg-hmo: Fix the logic for the horizontal trigger position in config_set()

This patch fixes the logic calculating the trigger position as well as the
(hopefully) last remaining locale issue.
hameg-hmo: Add the TRIGGER_SLOPE entry to config_list().
hameg-hmo: Add missing cases in config_get().
Replace 'probe group' with 'channel group' everywhere.

The name 'probe' (and thus 'probe group') is a relic from the times when
sigrok was mostly about logic analyzers. Nowadays we support a lot more
device types where 'probe' is not really a good term and 'channel' is
much better suited.

This fixes parts of bug #259.
Replace some 'pg' with 'cg'.

(since 'probe groups' are now called 'channel groups')

This fixes parts of bug #259.
Replace channel_group.probes with channel_group.channels.

This fixes parts of bug #259.
Consistently use 'cg' for channel group variables.

This matches how we consistently use sdi, devc, and so on all over
the code-base.

This fixes parts of bug #259.
Rename 'struct sr_probe' to 'struct sr_channel' everywhere.

This fixes parts of bug #259.
Replace 'probe' with 'channel' in most places.

Also, consistently use 'ch' for channel variables. This matches how we
consistently use sdi, devc, and so on all over the code-base.

This fixes parts of bug #259.
Rename sr_probe_new() to sr_channel_new().

This fixes parts of bug #259.
Rename various *PROBE* macros to *CHANNEL*.

This fixes parts of bug #259.
Rename a few more API calls with 'probe' in their name.

This fixes parts of bug #259.
A few more random 'probe' to 'channel' changes.

This fixes parts of bug #259.
hameg-hmo: Change some PG_/pg_ names to CG_/cg_.

This fixes parts of bug #259.
rigol-ds: Add the TRIGGER_SLOPE entry to config_get() and config_list()
rigol-ds: Don't close SCPI handle we didn't open.
Various drivers: Drop some unneeded lines.
demo: Fix typos.