infraga plot map using --> --rcvrs-file

[jl-miller]

to plot stations using --rcvrs-file sta.txt ......... the txt file needs two entries to plot

this doesn't work
43.09099 -107.9543

this does work
43.09099 -107.9543
0.0 0.0

the error for the top one is "Invalid Receivers file. Omitting from plot."