Update README.rdoc

mainly spell checking plus the mention of Debian/Ubuntu in the first para
Merge remote-tracking branch 'proventa/master' into zabbix-api
allow ip as interface
correct existence check for item
fix exists? and destroy of triggers
missing include Zabbix
inc timeout
typofix for librarian-puppet

needs to go on master for lots of use cases ASAP!
remove invalid ~ dependency

for librarian-puppet and needed ASAP
not working and breaking old puppet/facter versions
wrong type of id quieried
auto require hosts on things that depend on them
allow trigger dependencies
typo
force apps to be an array
move to official repo
correct typo
auto add host to zabbix
more sane group default
normalize group names to array