base poly issues: read description

poly was changed for keeping communication range of base from cell
centre but it was also being used for agent-agent range checks. So now
it is set back to boundary and for base-agent connectivity poly is
computed again
potential gradient - confirm with sir

potential gradient was for bias of path towards base. Also used in case
of network failure. but should it be used for role allocation...to be
discussed...am still thinking...till then it is length of
path(considering all edges as one.)
fixed poly problem

by changing poly in base definition at all places it was causing
problems. Now for base-agent connectivity compute new poly from cell
centre