Prepare for 1.6.0: http auth, clean-up, refactorings

Squashed commit of the following:

commit 1ee0c1f00e57c9326ba4373390a70aa5e39bed90
Author: Thomas Schank <DrTom@schank.ch>
Date:   Thu Jul 31 10:25:54 2014 +0200

    ....

commit 646a6dd59103994a1e35d684960317824d7e200a
Author: Thomas Schank <DrTom@schank.ch>
Date:   Wed Jul 30 15:40:47 2014 +0200

    Allow and respect null values for port

commit 9cd4d1e5a2b7c97e164970e759ad6e27c899a359
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Jul 28 18:35:01 2014 +0200

    Upgrade clj-utils and major clean-up

commit e55a0fef424d7edd7fe1af5ac5b8e68cf91b253e
Author: Thomas Schank <DrTom@schank.ch>
Date:   Wed Jul 23 08:39:32 2014 +0200

    Use utils/http for sync trials

commit b564897923a836fb6da991a5403e19f624fe4b9a
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Jul 22 22:53:51 2014 +0200

    Update clj-utils (http)

commit e51ec637f779fbe03ea2ae870d06bc48b90288c5
Author: Thomas Schank <DrTom@schank.ch>
Date:   Tue Jul 22 15:30:51 2014 +0200

    Add http authentication