Import R 3.1.0
Merge branch 'vendor'

Conflicts:
	configure
	src/include/config.h.in
	src/main/arithmetic.c
	src/main/envir.c
	src/main/gram.c
	src/main/gram.y
	src/main/logic.c
	src/main/main.c
	src/main/memory.c
	src/main/subassign.c