changed resource creation to take this ptr instead of context ptr. Removed
context arg from Material::CreateUntracked. Made untracked resources have an id
of zero instead of an id of garbage. fixed mat doc comments to use new res_buf method names.
Merge pull request #626 from rwcarlsen/res-this

changed resource creation to take "this" ptr instead of context ptr.
removed supply_demand and action_building namespace. closes #248.