improvements to HTML template

* HTML5
* custom font for better screen readability
* "green screen" when there are no problems
* "ambient color" reflecting worst status in background
Merge pull request #1 from trehn/pimp-my-html

improvements to HTML template
htmlios: Sort items by status, hostname, service
htmlios: Print error when curl fails
htmlios: Hide scroll bar
htmlios: "-E" to exclude services
htmlios: Sort "critical" over "unknown"
htmlios: Show "okay smiley" when everything's okay
htmlios: Larger main font size