docs: fix a markup bug in the Developer Manual

Remove a blank line that messes things up.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: include homing state diagrams in the Code Notes

Build-depend on graphviz, which provides dot, which converts diagrams
in .dot format to .png and .svg and probably other things.

Teach the docs Submakefile to auto-build .pngs and .svgs from .dots.

Include the existing homing state diagrams in Code Notes.

Ignore the newly generated .svg files.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: better asciidoc dependency generation

This makes it accept both "image:" and "image::" for asciidoc image
inclusion.

Both are used as valid examples in the asciidoc docs, with no mention
of any difference between them.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
Fix motion-type docs in motion manpage

Signed-off-by: Chris Radek <chris@timeguy.com>
docs: add punctuation

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: don't call the HAL tutorial "Advanced", because it's the one to start with

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: this is more of a basic reference than a tutorial

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: clean up the Basic HAL Reference intro a little bit

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
docs: minor reorg of HAL docs

Move the tutorial up, and the reference down.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
Fix motion-type docs in motion manpage

Signed-off-by: Chris Radek <chris@timeguy.com>

Conflicts:
	docs/man/man9/motion.9
Merge remote-tracking branch 'origin/2.6'
add liblinuxcnc-ui, a library for UIs to control linuxcnc

So far it just has new() and free(), and the build framework, and the
test framework.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
add a readme

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
lui: add connect()

Connects to Command, Status, and Error NML channels.

Wait for the first Status message before returning success.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
lui: add estop() and estop_reset()

And some infrastructure to send Command NML messages and wait for them
to be received by Task.

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
halui: use lui for estop

Connect to NML twice: once by hand (like before) and once via
linuxcnc-ui (lui).  Use lui for estop() and estop_reset().

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
lui: add machine_on() and machine_off()

Signed-off-by: Sebastian Kuzminsky <seb@highlab.com>
lui: introduce struct for positions

Signed-off-by: Jeff Epler <jepler@unpythonic.net>
lui: framework to autogenerate getters

Signed-off-by: Jeff Epler <jepler@unpythonic.net>
halui: use lui getter for old task.state

Signed-off-by: Jeff Epler <jepler@unpythonic.net>