Adapt to work with GHC 6.12

- Adapted the package to work with GHC 6.12
- Plugins that depend on the old base3 are currently
  not correctly loaded as the plugin loaded misses
  the dependence on syb (leading to unresolved symbols)
- Cleaned up most of the testsuite (there are still
  some outstanding failures, of which only one
  demonstrates a bug in the plugins library as far
  as I can see — see previous bullet point)
- Cleaned out a little cruft (but more could be done)

testsuite/build.mk

@@ -13,7 +13,7 @@ REALBIN=	./Main
 API_OBJ=	api/API.o
 
 INCLUDES=   	-i$(TOP)/testsuite/$(TEST)/api
-GHCFLAGS=   	-Onot -cpp -fglasgow-exts
+GHCFLAGS=   	-O0 -cpp -fglasgow-exts
 
 .SUFFIXES : .o .hs .hi .lhs .hc .s