Output enhancement

[seletskiy]

Following features are added:

• url-encode '[]' in the urls to suck less with terminal urlselect;
• substitute '$N' strings in the item names with proper values;
• (!) -d -dd -ddd flags for the providing more info about triggers (last item value, last item change, item description);

• (!) --stacked and --normal to obtain links to the stacked and normal composition graphs.

  umbermensch usage: xdg-open $(zabbixctl -L 'rabota-es-*' /cpu usage from quota --stacked)

[kovetskiy]

merged, thanks, great work