1.19.1
Merge the new autolibs help page.
port extract before update on FreeBSD
detect Amazon Linux AMI, fix #1682
fix running amazon requirements, update #1682
do not fail in update-system when in read modes, update #1724
improve autolibs error, fix detecting errors, closes #1724, update #1720
Merge pull request #1725 from wayneeseguin/bugfix/find_active_macports_packages

check only for active macports packages, cache the list, closes #1723
Merge pull request #1727 from theschoolmaster/debian-ubuntu-multiarch-support

debian/ubuntu multiarch dependency checking
Merge pull request #1733 from jasiek/master

Checking for the existence of patch via a package manager is not necessary
do not try port for smf osx requirements, fix #1736
fix code to detect failing pipes, fix #1741
Add -B flag on FreeBSD during compilation. Fixes ruby build issues on FreeBSD 8.x
Fix inverted logic in FreeBSD make -B change
fix permissions only of extracted files not everything in target, also removes target files, fix #1680
improve extraction errors detection, fix rights for travis, update #1680
fix extraction temp on FreeBSD, fix travis rights fixing, update #1680
better sysctl use if it's not in PATH
fix rvm_requiremnts_fail_or_run_action, update #1720, update #1724, found: http://stackoverflow.com/questions/15587298/cant-install-ruby-1-9-3-via-rvm-in-os-x-lion-even-with-with-gcc-clang/15587558?noredirect=1#comment22320984_15587558
fix update-system and error messages, improved autolibs level detection in update-system, update #1720, update #1724

Conflicts:
	scripts/functions/build_requirements