Fix bug in right_node macro
Fix bug when updating regions in their place in the tree

Must call rb_tree_node_updated when 'start' or 'end' is adjusted
in order to propagate the new subtree information toward root.
Fix buggy region_print

Seems like VG_(umsg) don't understand the "%.*s" format.
Add rb_tree_check and other assertions
Refactor consistence use of rb_tree callback typedefs
Add 'do_update' argument for update_subtree

to be passed as false by assertions without mutating the tree.
Add CHECK_TREE macro with 'offender' argument
Bug fix in rb_tree_remove

Must do update_subtree of y->parent even if y is unchanged
as y has been removed and then reinserted into the tree.
Remove MH_DEBUG