Add config info for device type and limit config keys.
More robust searching for config keys.
atten-pps3xxx: Publish driver options.
cem-dt-885x: Publish driver options.
demo: Rearrange driver and device options.
scpi-pps: Publish driver options.
asix-sigma: Publish driver options.
Change SR_CONF_FILTER key to a boolean type.

This was an ill-defined string before, now it's simply something
you turn on or off on a channel.
hantek-dso: Fix driver/global/channel group config keys.

This was way behind and did not yet support channel groups.
Make sr_dev_inst_connid_get() available without libusb
zeroplus-logic-cube: Add support for AKIP-9101.

Thanks to Nikita Nazarenko for the patch.
fx2lafw: Fix wide (16bit) sampling case.

This fixes bug #373.
Only sr_dev_inst_free() should free channel groups.
ols: Fix a serial port related issue on FreeBSD.

Add sp_drain() to ensure bytes have actually been transmitted
over the wire.

This fixes bug #414.
Brymen BM25x: Drop unneeded _ser/_SER suffix.

There's only one cable for this DMM, thus there's no need for a
_ser/_SER suffix or for specifying the cable name.
session_driver.c: Allow querying of SR_CONF_CAPTURE_UNITSIZE.
Add sr_dev_inst_channels_get() and sr_dev_inst_channel_groups_get().
Make 'struct sr_dev_inst' opaque.
Constify the sdi parameter of all sr_dev_inst_*() getters.
bindings: Use getters now that 'struct sr_dev_inst' is opaque.