Hydrograph does not work with seasonal gauges

[nickyrong]

The hydrograph tab will run into error when the gauge is seasonal:

Warning: Error in :: NA/NaN argument
168: %>%
167: renderPlot [/ShinyCFA/server.R#287]
165: func
125: drawPlot
111: reactive:plotObj
95: drawReactive
82: origRenderFunc
81: output$hydrograph
1: runApp

[nickyrong]

The hydrologic regime plot is generated by a function from the FlowScreen package (there are some not yet implemented trend test functions commented out in the code also from FlowScreen package).

However, it does not looks like FlowScreen is being actively developed (last commit in 2019). It is therefore better to move away from FlowScreen and use similar functions from fasstr instead.