Add a Liquid filter `to_xpath`, which quotes a string for use in XPath expression.
Move the Save button right under the options.

It's nice for each Agent to have a good, detailed description, but
currently the Save button will be gone too far below when the
description is very long in height.
`uri_escape`: Do not fail when nil is given.

Do just the same as the standard filter `url_encode`.
HipChatAgent: username length limit is 15 chars

Also try to use travis-cis bundle caching
Merge pull request #467 from dsander/hipchat-username

HipChatAgent: username length limit is 15 chars
Merge pull request #465 from knu/move_save_button_up

Move the Save button right under the options.
Extend the spec to give a better idea on how to use `to_xpath`.
Merge pull request #462 from knu/liquid-to_xpath

Add a Liquid filter `to_xpath`, which quotes a string for use in XPath expression.
Make `to_xpath` stringize a non-string operand as the standard filters do.
Fix specs for the new stuff in DOT output.
Rename "target" to "control target".
Merge remote-tracking branch 'origin/master' into scheduler_agent
Fix a bug with edge line styling.