sweq_ggplot: Plot SWEQ
In robertsy/assimilr: Local Ensemble Kalman Particle Filters

plot the state, the ensemble and the observations all together

sweq_ggplot(state, ens = NULL, obs, h_lim = c(90.02, 90.3),
  selected_field = c(1, 2, 3), params = NULL, tit = NULL,
  norain = FALSE, h_ylim = c(89.9, 90.6), r_ylim = c(0, 0.075),
  u_ylim = c(-0.045, 0.045), field_names = c("fluid height", "rain content",
  "wind"), psize = 1)

`ens`	the ensemble matrix
`obs`	the observation object
`selected_field`	to plot only some
`params`	as from sweq_simulate$params
`tit`	optional title
`field_names`	for plotting
`psize`	size of observations
`the`	true state
`hlim`	the vector of hr,hc to plot as dotted lines
`norain=T`	means that we plot the no-rain observations
`*_ylim`	for enforcing plotting limits