Fixed the spelling of the word 'occurred'.
Fixed the call to XEXIT in sighandler_crash.  Someone forgot about the first argument (err_type), and this was causing me to get weird error messages like 'StandardError: Exiting on signal %s (%d) occured at <global.c>:423 in sighandler_crash SIGSEGV'.  Note that the %s and %d failed to be substituted and the signal number doesn't appear at all.
Merge pull request #8 from DavidEGrayson/pull_request_1

Fixed spelling, fixed formatting of an error message.