Renamed label to message to clarify, added column_num, type and data instance variables.
Allow static constants
Improvements to StyleError and StyleRubric to keep track of column numbers and additional data about the error.
Merge branch 'side_branch'
Operator spacing check: report error for incorrect spacing around each type of operator on the line
Correct line numbers for break and indentation checks, correct column numbers for operator spacing checks (changed return value of check_operator_regex), errors are sorted by line number and column number