Release 0.1.9

- fix unbound variable in debian element
- fix syntax error in GRUB_OPTS env var handling
- add rsync to the package list used by debootstrap
- update the image name for RHEL Guest Image (bug 1286568)
- add $EXTRA_ARGS back to yum call (bug 1287142)
- fixup all occurrences of REPONAME for replacing '-'
- move install type enablement into base element
- baremetal element: enable stable interface names
- support adding DHCP interfaces one at a time
- add RHEL 7 image element
- improve usability of the source-repositories cache
- enable extlinux support for (non-Ubuntu) Debian platforms
- bash eval the lines in source-repository scripts
- add libaio1 to libaio pkg map for fedora
- add nfs-common package mapping
- update openSUSE package mapping for libffi-dev
- add apache2 mod_wsgi pkg map for suse
- create a git manifest from source-repositories
- additional swift storage service mappings
- RHEL Package maps for build-essential, python-dev and libz-dev
- add redhat-common element
- update README formatting and content
- updated from global requirements
- better apt-sources docs