Update param.net docs

Outlines the time-varying parameters
Implement dual rec.rate initialization for netsim
Add run arg back into comp_plot generic
Update website on main vignette
Update comp_plot docs
Add variable rec.rate initialization to ICMs
Remove pdf doc
Another attempt at comp_plot
Fix typo
Add time-varying recovery rates to netsim
Incorporate TV rec rates into test
Minor comp_plot doc update
Update docs for param.net
Update NEWS

Now using issue numbers linked to NEWS
Add two issue refs to NEWS
Another attempt at comp_plot methods
Merge pull request #177 from statnet/netparams

Work on network model parameters