Fix assorted typos in xmas_gats_not_an_angel.as
colour -> color
colour -> color
colour -> color
colour -> color, sulphuric -> sulfuric

'sulfiric' is the standard spelling in both British and American English.
colour -> color, ellipses fixes
Merge pull request #434 from Strongbird/master

Fix some typos, fully move to American English spelling of 'color'