[evlatests] L band focus

[Ken Sowinski]

I wrote a script to determine optimal focus at L band.  This
was done at the default observing frequencies around 1400 MHz.
Most antennas were found to have significant focus offsets
and all, except 17 which was out of service, have been adjusted.
ea26 was the worst of the lof, off by about 1/3 of a wavelength.
This should noticably improve Rick's efficiency estimate for
many of the antennas.

Further work is to to this at the band edges.

Ant   New    Old   Diff
11   -2.5   -1.5   -1.0
13   -4.0   -3.35  -0.65
14   -6.0   -3.0   -3.0
16   -9.0   -8.0   -1.0
17   ----
18   -3.0   -3.0    0.0
19   -5.0    0.0   -5.0
21    0.0    5.0   -5.0
23    0.0    0.0    0.0
24   -5.0   -3.0   -2.0
25   -3.0    2.0   -5.0
26   -7.0    0.0   -7.0