ACSIS: Call inout_jsatile from inout in JSA mode

If the respective JSA_TILES uhdr is set, the ACSIS Frame and Group
inout methods now call inout_jsatile automatically.
heterodyne: Check that the velocity limits are defined.
heterodyne: Increase the arbitrary maximum pixel size.

After discussion with Jan Wouterlout, increase the maximum pixel size
to 1000 arcsec.  He had bone-fide 720-arcssec data being mangled by
the previous 100-arcsec limit.
heterodyne: Make better provision for sloping baselines.

In some recent (20140520 #30-32) data there was an appreciable slope
in the baselines.  Without this extra step the initial historgram
bounds were too extended and it lead to large sections of baseline
being omitted (masked) from the non-linearity tests.  After this
change the initial histogram delineates the peak from the emission
more effectively, and there is better convergence to a sensible
peak value.  The result is the emission line is masked not portions
of the baseline.
heterodyne: Increase maximum non-linearity threshold.

It's another of these arbitrary where to set the bar fudge constants.
Rather than an absolute limit I've applied a maximum above the mode.
This may work well for some recent data the exhibits a new kind of
hybrid sloping sections along the spectral axis comprising
high-frequency noise.  The effect is to raise the global non-linearity
measure such that the previous 0.01 threshold was too low. As to
whether this threshold is now too high for other data I do not know,
and requires more testing.  It ought to be reasonable as it's a
constant above the mode.

An example of this noise can be viewed in a20140520_00032_01_0001, H08.

_FLAG_HIGHFREQ_INTERFERENCE_SPECTRA_ doesn't deal with this new strain
of h.f. noise yet.  If that were changed it may have an impact here.