Added date_atus() to determine date when ATUs reached. (#9).
Add latex = FALSE argument to gss_plot() to turn off use of LaTeX to add degree symbol to y-axis label.
gsdd 0.2.0
Added complete = FALSE argument to gsdd_vctr() and gss_vctr() to specify whether the vector of water temperatures represents the complete growing period.
Modified gsdd(), gdd(), gss() and gss_plot() so that a growing season is not considered to be truncated at the start and/or end if the water temperature is above the threshold at the start and/or end dates.