change names of check class methods that return strings, fix /checks API endpoint
Merge pull request #642 from flapjack/641_checks_errors_api

change names of check class methods that return strings, fix /checks API endpoint
Quote ncsm example to clarify parameter

 -  If the user enters a number by itself, Ruby's YAML type inference treats it as an integer, causing Flapjack to fail during bootup when it tries to call `downcase` on an int. 
 - @jessereynolds said I could commit this directly to master.
 - YOLO
Quote ncsm example to clarify parameter

 -  If the user enters a number by itself, Ruby's YAML type inference treats it as an integer, causing Flapjack to fail during bootup when it tries to call `downcase` on an int.
 - @jessereynolds said I could commit this directly to master.
 - YOLO
Merge branch 'master' of github.com:flapjack/flapjack
Merge branch 'master' into more_api_check_methods