add flash_service and flash_directive
Create styles for notice, alert, warning, and error flash messages.
add availability check after sign in to make sure the current mod hasn't alerady been done by user
Merge branch 'flash-and-messging' of github.com:LiminalSoftware/Categorize into flash-and-messging

* 'flash-and-messging' of github.com:LiminalSoftware/Categorize:
  Create styles for notice, alert, warning, and error flash messages.
Merge remote-tracking branch 'github/flash-and-messging'

# By Bryan White (1) and nembus (1)
* github/flash-and-messging:
  Create styles for notice, alert, warning, and error flash messages.
  add flash_service and flash_directive
Merge branch 'flash-and-messging'

# By Bryan White
# Via Bryan White
* flash-and-messging:
  add availability check after sign in to make sure the current mod hasn't alerady been done by user