[tdwg] Interactive key update

New additions to Carex Interactive Key -

Added an "AVOID" character state to certain characters. It is a "neutral" character that allows a user to skip a character. This character was added to remove a character from the "best character" list. If required, the character can easily be unchecked and used in the same determination. It is present in "*country, state and floristic zone*" and in "*Carex section*".

Added histograms to certain characters and states to allow the user to visualize the data within the data matrix. Error and absence data are not represented (for clarity). All histograms can be easily seen by expanding the features tree.

Key at http://utc.usu.edu/keys/Carex/Carex.html

Any input is greatly appreciated, Tim