support: add partial Fedora support

This patch marks Fedora 19 and 20 as partially supported, adds a new
support script (install-rpm-dependencies), makes all of
install-deb-dependencies, remove-deb-anty-dependencies and
install-ppa-dependencies gracefully exit if dpkg is not installed and
lastly adds requirements/rpm-*.txt files that capture most of the
content of their requirements/deb-*.txt counterparts.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>

fixup
support: update support IRC channel name

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
support: require basic i18n packages

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@canonical.com>