ElkMR: Function to calculate movement rates of elk
In khuggler/TediousEcology: Data Formatting for Various Analyses in Ecology

Merge cleaned GPS data with the movement rate of elk

1	ElkMR(gps, startdates, enddates, subspp, subsex)

`gps`	data.frame of gps data
`startdates`	vector (date format) of the start dates to subset GPS data
`enddates`	vector (date format) of the end dates to subset GPS data
`subspp`	what species to subset
`subsex`	what sex to subset

Returns a data.frame with all gps data, AnimalID, Sex, and Species, and Reproductive Status (Repro or Non-Repro)

1	ElkData<-ElkMR(gps = yourgpsdata, startdates = c('2017-05-01', '2018-05-01'), enddates = c('2017-09-01', '2018-09-01'), subspp = "ELK", subsex = "F")