Modified addData function to overwrite already saved characters and fixed a bug with the viewParty button

Added an if statement to addData function to check if the character
being passed to it had already been created so it can instead
"overwrite" the old data with the new.  Also, disabled the "view party"
link on the page when the edit page is onscreen, as selecting this
breaks the toggle function and allows the ul and li elements to "stack"
at the bottom of the page.  whoops...