[ ] Cannot Reroll after assigning to a category
[ ] Cannot Roll (new) without assigning to a category
[ ] After assigning roll to category, clear the current roll
[X] Be able to keep/hold 0-5 of the dice, re-roll the rest (up to 2 re-rolls) [X] Display individual dice as checkbox items [X] Click/check to keep that die [X] Upon reroll click, do a POST of the kept die(s) [X] Enable reroll button based on number of rolls [X] Don't enable reroll button until after initial roll