dataPurification_SKPSP() now removes every measurement of a tree that died of a cause in codesToExclude; it stopped with an error before (#24).getPSP() gains codesToExclude, damage agent codes to exclude by source (BC, AB, SK, NFI) (#24).getPSP(forGMCS = TRUE) now removes BC trees damaged by mountain pine beetle: it passed the code "IMB", which matches no BC code, instead of "IBM" (#24).