Adjust vectors

[slucey]

Minor fix to allow adjust.scenario to work on a vector of groups rather than one at a time.

[kaydin]

Works with following test script. Note that "groupto" can only be a single group (not a vector) so this can be applied across multiple prey for a single predator, but not across multiple predators.

`library(Rpath)

unbal <- REco.params
bal <- rpath(unbal)

scene0 <- rsim.scenario(bal,unbal,1:100)
scene1 <- adjust.scenario(scene0, parameter="MzeroMort", group="Seabirds", value=5 )
scene2 <- adjust.scenario(scene0, parameter="MzeroMort", group=c("Seabirds","Whales","Seals"), value=c(2,3,4))
scene3 <- adjust.scenario(scene0, parameter="MzeroMort", group="all", value=3)

scene1$params$MzeroMort
scene2$params$MzeroMort
scene3$params$MzeroMort

scene4 <- adjust.scenario(scene0, parameter="VV", group="OtherForagefish", groupto="Seabirds", value=5 )
scene5 <- adjust.scenario(scene0, parameter="VV", group="OtherForagefish", groupto="Zooplankton", value=5 )
scene6 <- adjust.scenario(scene0, parameter="VV", group="all", groupto="Seabirds", value=5 )
scene7 <- adjust.scenario(scene0, parameter="VV", group=c("OtherForagefish","Discards","JuvRoundfish1","JuvRoundfish2"),
groupto="Seabirds", value=c(1,5) )

scene4$params$VV
scene5$params$VV
scene6$params$VV
scene7$params$VV`