Change type of SR_CONF keys to uint32_t.
Consistently use 'devopts' variable across all drivers.
Consistently use 'scanopts' variable across all drivers.
beaglelogic: Add missing scan options, and cleanup.
Publish config key capabilities.

Every driver now publishes its device option config keys, i.e. the
list fetched with sr_config_list(SR_CONF_DEVICE_OPTIONS), with a
set of flags indicating which methods are implemented by the driver
for that key.

The config keys are OR'ed with any combination of SR_CONF_GET,
SR_CONF_SET and SR_CONF_LIST. These are defined as the high bits
of the uint32_t config key. Clients can OR config keys with
SR_CONF_MASK to strip out these bits. This mask will be kept up to
date if other bits are added to the capabilities list; clients MUST
therefore use SR_CONF_MASK for this.

Some keys don't have capability bits added, such as the informative
device type keys (SR_CONF_MULTIMETER, SR_CONF_OSCILLOSCOPE, ...) and
SR_CONF_CONTINUOUS.

Scan options do not have capabilities bits.
yokogawa-dlm: Don't implement dummy scan options.
Typos and consistency fixes.
input/chronovu_la8: Fix broken I/O loop.
session: Don't try to send packets if no session has been set.

This indicates a bug, but let's not segfault if it happens.
colead-slm: Properly check acquisition sample limit.
demo: Fix pattern mode and amplitude option publishing.
Add usb_get_port_path() helper function

There is currently no way to uniquely identify USB devices in
libsigrok. It uses the "bus.address" scheme which is only
constant as long as the device remains attached to the bus.
In order to allow USB device persistence in PulseView, devices
need to provide a unique identifier even in absence of a
serial number. This function is the first step as it provides
the ability to query the physical location of a USB device.
Add serial_num and connection_id fields to sr_dev_inst
serial_stream_detect: Make read nonblocking.

This code implements its own waiting based on baudrate, so the read itself
should be nonblocking. In general it will have been already, since drivers
almost universally use the SERIAL_NONBLOCK flag.
serial_readline: Implement using sp_blocking_read.
manson-hcs-3xxx: Mark serial read call as blocking.

This driver opens the port without the SERIAL_NONBLOCK flag, so this call is
already a blocking one.
colead-slm: Mark serial write call as blocking.

This driver opens the port without the SERIAL_NONBLOCK flag,
so this call was already blocking.
serial-dmm: Mark serial read/write calls as nonblocking.

This driver opens the port with the SERIAL_NONBLOCK flag so these calls were
already non-blocking.
serial-dmm: Remove SERIAL_NONBLOCK flag.

All serial read/write calls in this driver are now explicitly
nonblocking so there is no need for this flag.
agilent-dmm: Mark serial read call as nonblocking.

This driver opens the port with the SERIAL_NONBLOCK flag, so this call is
already a nonblocking one, and is handled appropriately.