added avl_tree example to cil regression test
proved cil avl_tree find & find_min
fixed missing deleteLocals when returning from a function call
changed avl example from signed to unsigned
minor
strict to seqstrict
subsorted sizeof' to Exp
final incomplete effort in proving avl_tree insert/delete
Merge pull request #52 from yilongli/java_rewrite_engine

incomplete effort in proving avl_tree insert/delete