Minor Typo and Packaging Fixes

This is a pure bugfix release with no functional changes.

Bug Fixes

• Fixes a bunch of typos found by Jakub Wilk

Debian Packaging

• Compliant with Debian Policy 4.1.5.
• Build-dependencies updated for ruby-ronn package split-up.
• Build-Conflicts with libperl-critic-freenode-perl for now.
• Replace /usr/share/doc/unburden-home-dir/html/search/mustache.min.js with symlink in unburden-home-dir-doc and recommend libjs-mustache.
• Switch to debhelper compatibility level 11.