Add seed data

These seed data are useful during development, especially when working
with the UI and you don't want to deal with the overhead/hassle of
setting up actual nodes to manage.

Load them by running `rake db:seed`.
Merge pull request #503 from crowbar/kwwii-menu-fix

Fix Menu positioning
Merge pull request #504 from crowbar/jamestyj-linux_compile

Simplify linux_compile.sh
Merge pull request #505 from jamestyj/jamestyj-seed

Add seed data
adding build instructions to devguide
Merge pull request #508 from simonjj/pull-req-master-da6e25e7b67efcaf4dc80d0aebe34f787a46b840

moving build instructions from wiki to devguide doc directory [1/1]
making title more website friendly
Update devtool-build.md
Updated download location to point to Sourceforge
Updating downloads to point to downloads page instead
blame it all on me, last update to this link
I am being slow, forgetting that we need absolute links
Zap explicit numeric ordering for barclamps.

Instead, we now rely on barclamp:requires clauses in the crowbar.yml
coupled with an implicit dependency on the crowbar barclamp.
Add role_prereqs table.
Add model for tracking role -> role prerequisite dependencies.
Transition role into using explicit dependency orderings.
Add the on_same_node flag to the role_prereqs table.
Add the role_nodes table.
This will replace the attrib-based method of binding roles to nodes.
Add the role_nodes class.
Start node and role refactor.