Vela corrections

Makes the corrections to the fermi analysis we discussed... although npred counts now goes down to 145 which seems low?
Put the analysis parameters you use several times as variables at the top:
```
# Analysis parameters
RA=128.836063542
DEC=-45.176431806
GLON=263.552038198
GLAT=-2.78733656284
```
and then use them as `$RA` etc. in the commands below.