Docs: fix incorrect example and add info about tabs

Signed-off-by: John Thornton <jthornton@gnipsel.com>
Touchy: enable MDI multi-turn arcs
fix typo, preventing remote NML clients talking to lcncserver

Signed-off-by: Alex Joni <alex_joni@users.sourceforge.net>
Signed-off-by: Kim Kirwan <Kim@KimKirwan.com>
test that a basic nml-using UI can be built using only header files we publish
Test header file sanity

For each header which we ship (with a few tiny exceptions), test that simply
preprocessing it on its own does not lead to any errors due to
"#error" directives or missing #includes.
must ship this header file

.. without it, the to-be-merged test "build/ui" will fail at the site where
emc_nml.hh is included.
Merge remote-tracking branch 'origin/v2.5_branch'