v1.5.3

ControlSystems v1.5.3

Diff since v1.5.2

Closed issues:

• Stable docs not linking correctly? (#570)

Merged pull requests:

• make docs examples strict (#777) (@baggepinnen)
• Improve error message for wrong u dimension in lsim (#778) (@baggepinnen)
• even better error messages for wrong u in lsim (#779) (@baggepinnen)
• provide an error hint on plotting (#780) (@baggepinnen)
• fix delaymargin for systems with multiple gain crossings (#781) (@baggepinnen)
• add methods to are, lyap taking system (#782) (@baggepinnen)
• add extended_gangoffour (#783) (@baggepinnen)
• Fix links in README file. (#784) (@pietrop88)