updated readme files for the macosx distribution
fix readline makefile
fix the way "run" detects an interrupted subjob so it can
signal an error.  Return code 512 is returned by a process
that exits with exit(2), so does not signal an interrupt.

I discarded the case where 1002 is returned, since it's a mystery.
Merge branch 'release-1.6' of github.com:Macaulay2/M2 into release-1.6
update debian changelog for the new version number
Merge branch 'release-1.6' of github.com:Macaulay2/M2 into release-1.6
punctuation
Merge branch 'release-1.6' of github.com:Macaulay2/M2 into release-1.6
fix interrupt handling, which has been broken for a long time
fix package CompleteIntersectionResolutions:
  a function was returning an error message instead of calling "error"
  some examples called "random" but not setRandomSeed
merge changes from release-1.6 into master
update final-checks
increase a time limit for a test
Merge branch 'release-1.6' of github.com:Macaulay2/M2 into release-1.6
fix a failing example in package CompleteIntersectionResolutions
make --int command line option not suppress SIGALRM handling
shorten the alarm time in an example so it always fires at least once
set DebuggingMode to false for all packages
Merge branch 'release-1.6' of github.com:Macaulay2/M2 into release-1.6
add a cast to remove a warning message