0.6.11.12:

0.6.11.12:
	moved !PACKAGE-COLD-INIT earlier in cold init so that KEYWORDP
		will work earlier
	tidied up UNIX-SIGNAL machinery: no more DEFCONSTANTs,
		no more re-interning, no more descriptions
	tweaked RUN-PROGRAM to use UNIX-SIGNAL-NUMBER function instead
		of old bare SIGFOO constants
	It's easier and nicer just to coerce all RUN-PROGRAM args
		than to require that they be SIMPLE-STRINGs.
	made test/*.test.sh use local sbcl, not installed sbcl, just
		as other tests do