Fix 16-bit to 8-bit color conversion

We need to divide by 256 not 255 otherwise some colors will be outside of the
valid range.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
channel_color_settings_cb(): Free color chooser dialog

Call gtk_widget_destroy() to free the color chooser dialog and not leak any
memory.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
channel_color_settings_cb(): Set current color as active color

Set the color chooser's active color to the current color of the channel before
showing the dialog.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
oscplot: Use lighter colors for the default colors

The current default have a rather bad contrast against the black background. Use
lighter colors instead. And while we are at it also add some more colors.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Osc: Add more validation rules for the channel selection
The new HDL cores do not support any combination of enabled channels
Osc: Fix a missing mask for 4-channel devices
- the mask representing all channels was missing (0x0F)
Osc: Fix the mask for 4 enabled channels
DAQ2: Turn all DDS scale comboboxes into spinbuttons
Fmcomms2: Add to plugin a selection list for tx channels
Fmcomms5: Remove "Dac Output Buffer" option from the plugin
plugins/datafile_in.h: Add extra check

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
plugins/fmcomms2_adv: Update FMCOMMS5 support

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
plugins/fmcomms2: Fix Bug when running remote

Assume we're up to date when remote

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
plugins/fmcomms2: Update FMCOMMS5 Support

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>