Released v1.4.0

Most important changes:
1. cx_secured_buf() and cx_free_sec_buf() are far more easier to use now, since the user no longer needs to care about secm_t - in fact, this struct is now "private".
2. new funcion: CX_CATCH_SIG_MASK() allows to register several signal handlers in a single call.

Manpage updated and improved. See ChangeLog for full list of changes.