fork the mysql_connections plugin to add per-user support
limit to ten the number of users by default
cosmetic fixes
reorder graph to, hopefully, fix stacking
limit and sort the config entries the same way as we sort values, based on values
overhaul graph display: remove total, make "current" the "limit"

i did this because I can't figure out how to *not* stack the lines
after the areas. furthermore, removing the limit is essential to have
a proper resolution in the display.
cosmetic
Merge pull request #417 from anarcat/mysql_per_user

fork the mysql_connections plugin to add per-user support