column names of coordinates change when spliting a moveStack

If you have a moveStack and split it the coords column names change, which than of course is passed on to the re-stacked move object. The same as in issue#3, this makes life somewhat complicated....

library(move)
data(leroy)
leroy@coords[1,]
# location.long  location.lat 
# -73.8988       42.7437 

data(ricky)
ricky@coords[1,]
# location.long  location.lat 
# -73.90426      42.84189 

mvstk <- moveStack(list(leroy, ricky))
mvstk@coords[1,]
# location.long  location.lat 
# -73.8988       42.7437 

mvstkL <- split(mvstk)
mvstkL[[1]]@coords[1,]
# coords.x1 coords.x2 
# -73.8988   42.7437 

mvstk2 <- moveStack(mvstkL)
mvstk2@coords[1,]
# coords.x1 coords.x2 
# -73.8988   42.7437