Update changelog & VERSION for 2.6.0~pre4
French doc update and cleaning

Signed-off-by: Francis Tisserant <tissf@free.fr>
Fix crash on debian wheezy + gcc4.7.2
Merge branch '2.6'

Conflicts:
	VERSION
French doc update: Document G5,G5.1,G5.2,G5.3 NURBS/spline commands

Signed-off-by: Francis Tisserant <tissf@free.fr>
tp: Skip tangent check if the previous segment is exact stop
Added an additional check for target velocity of the next segment to fix velocity overrun with slow acceleration machines
Added G61 and G61.1 distinction in TP

Added an additional value for termCond / canonMotionMode to represent
explicit exact stop (vs. exact path). Now, canon and motion pass one of
3 values as terminal condition (exact stop, exact path, or blend), and
the TP handles this accordingly. Exact path is the same behavior as
exact stop, EXCEPT when lines are tangent, in which case it does not
stop.
linuxcnctop: no need to specify tabstops as a string
linuxcnctop: indent continued value lines
Merge branch 'linuxcnctop-tweaks'
Rename comp to halcompile, to avoid several kinds of confusion

comp is part of MH ("compose"), and is also a hal component ("Two input
comparator with hysteresis"), so calling our compiler "comp" causes
trouble, in particular when the shell helpfully suggests you install mh.
configure: Choose highest-numbered version of tcl/tk

Otherwise, on my system (debian testing) which happens to have both 8.5
and 8.6 installed, as luck would have it tcl8.6 and tk8.5 were chosen
and configure complained about it.
rtapi: use proper type for rtapi_print_msg level
Remove unused define
milltask: don't link with ULAPISRCS

.. that's just the same stuff that's in liblinuxcnchal.so
configure: make missing img::png a configure-time failure
packaging: must build-depend on what configure checks for
Docs: 4 dashes before and after denote a code block

Signed-off-by: John Thornton <jthornton@gnipsel.com>
Docs: fix column alignment

Signed-off-by: John Thornton <jthornton@gnipsel.com>