Fixed search error with non-alphanum characters.
Changing the structure of character_controller

What I had before did not correctly match the specifications
App now behaves more like the program description.

Landing page is a simple search box where part of a character name
is entered. After searching, results are displayed on the page in
a list, and clicking on a character's name takes the user to the
show page, where details about that character are displayed.
Changed wording on link to search from show
Changed the cleaning method for the search string

..and moved it from the controller to the model.

No longer replacing non-alphanum characters...instead
using Regexp.escape since a name could conceivably have
dashes or underscores or something in it.