Merge commit 'b2eaac1' into dtls

* commit 'b2eaac1':
  Stop assuming chars are signed
  Add tests for CBC record splitting
  Fix tests that were failing with record splitting
  Allow disabling record splitting at runtime
  Add 1/n-1 record splitting
  Enhance doc on ssl_write()

Conflicts:
	include/polarssl/ssl.h
	programs/ssl/ssl_client2.c
	programs/ssl/ssl_server2.c