added automatic support for both ARC and non-ARC projects or compile options
added ARC and non-ARC tests
extra memory safety
Revert "Allow NSLinkedList to be used with ARC projects, as long as -fno-objc-arc is set"

This reverts commit 3e29c10f0b32a1366eaded7bc0b626452fe750b0.
Merge remote-tracking branch 'upstream/master'