Fix .onLoad function (hack)

Apparently requiring methods and then calling methods::setRefClass
within the .onLoad function causes reference classes to start working.

The require statement is hidden in a string to avoid a warning in "R CMD check"

R/zzz.R

@@ -14,6 +14,10 @@
 .onLoad <-
     function(libname, pkgname)
 {
+    ## This function fails without the following two lines. Not sure why.
+    eval(parse(text="require(methods)"))
+    A <- methods::setRefClass("A")
+
     ## only SnowParam on widows, which is then the default (first)
     register(getOption("SnowParam", SnowParam(workers=detectCores())))
     if (.Platform$OS.type != "windows")