removed has_many_polymorphs and used has_many :source and :source_type

fixes #2062 - Add max_trends setting

Do not use :class_name in has_many :through, missed on for class_params

removed puppet class include in index because it creates too many joins in a single query for sql-light to function properly.

removed class_name from all relationships that has_many :through as its invalid.

It seems like we hit a rails bug, where the joins were incorrectly created,
once removed, it was generated correctly.

reviewing the docs again, say that its ignored with hmt relation, so removing anyway.

puppet class form ui fixes.

fixes #1834 to get foreman running under ruby 1.9.3

fixes #2018 add forward slash to controller name of url_for() helper

added slash /unattended to other url_for calls

fixes #2023 - Don't try to save os=nil in the fact importer

I've tried to address all possible places where empty set of facts (e.g. we
dont have the facts just yet as its a brand new install) could lead to the
operating system value disappering.

i believe the issue happened because of a boolean == string compareing (e.g....