Character Counter (Chars.pm) - More triggers, quoted strings and better tests

Trying to get the DuckDuckHack experience first hand! I see that some of the docs are based on this instant answer, so no worries if you would prefer to leave the IA as it is.

Includes a bunch of tests for the triggers and the different expected behaviors. All currently passing.
@jagtalon while looking through all the code in the DuckDuckGo repo I came across this (https://github.com/duckduckgo/duckduckgo/blob/master/lib/DDG/Meta/Helper.pm) which installs helper functions into Goodie and Spice. We could easily add `String::Trim` into that so a `trim()` function could be provided to IA's to use.

Currently there seems to be many Goodies/Spice using the regex you suggested or String::Trim to accomplish the same goal.

Just a thought :)