make bin/jekyll executable

`bundle install` makes it executable and it should be anyway, since it
has the hashbang at the top.
cucumber: don't manually include assertions

It causes hard to debug infinite loops and it's done automatically
in recent versions of Cucumber anyway.
Changed the jekyll steps to write only the date and time for tests. This avoids timezone issues.
Fixes so that the timezone gets written when it explicit is specificied in a test
Document Jekyll's date_to_rfc822 and uri_escape filters on the site
Document uri_escape
Trying to edit my history to remove the mistakes
Merge pull request #1142 from kmikael/filters-documentation

Documentation for `date_to_rfc822` and `uri_escape`
Update history to reflect merge of #1142.
Merge pull request #1124 from jpiasetz/master

Change cucumber tests to not write posts with timezones
Merge pull request #1139 from scribu/cucumber-fix

Fix for #622 (Cucumber infinite loop)
Update history to reflect merge of #1124
Update history to reflect merge of #1139. Fixes #622.
Merge @mattr's history update with mine
Added JekyllGalleryTag to plugins.md
Merge pull request #1143 from redwallhp/changing-plugins-page

Added JekyllGalleryTag to plugins.md
Update history to reflect merge of #1143