new network data
fix bug
hack makexgmml.py...

...to implement changes requested by MH:

 1. make Erk and Akt nodes of equal size
 2. eliminate outer circle of nodes and edges
 3. make zero-edges light gray
 4. make outlines of nodes with at least one non-zero edge black

The solution of 1 also involved hacking the data files received
from MH to change their second and third lines from

Erk	1	0
Akt	1	0

to

Erk	0.5	0
Akt	0.5	0

Note that all the changes above were made "unconditional".  IOW,
there's no easy way to reverse them other than reverting to the
previous version of makexgmml.py.
update network images
new version of networks data
make makexgmml handle rtk & signaling
improve noclobberdict
update network images