Support specyfiying window/packet size per session
Support specyfiying window/packet size per session

Also update the documentation about values and the adverse effects
that changing them might create.

thusoy/paramiko,mhdaimi/paramiko,CptLemming/paramiko,davidbistolas/paramiko,digitalquacks/paramiko,varunarya10/paramiko,paramiko/paramiko,SebastianDeiss/paramiko,zarr12steven/paramiko,dorianpula/paramiko,rcorrieri/paramiko,jaraco/paramiko,selboo/paramiko,zpzgone/paramiko,esc/paramiko,mirrorcoder/paramiko,toby82/paramiko,remram44/paramiko,anadigi/paramiko,dlitz/paramiko,thisch/paramiko,Automatic/paramiko,fvicente/paramiko,redixin/paramiko,ameily/paramiko,reaperhulk/paramiko,jorik041/paramiko,torkil/paramiko