Removes hardcoded 'pivotal' username override from database.yml.example
[#70124412] - Eliminate some n+1 queries

 - pass presenter options when presenting workspace owner to eliminate a tags n+1 query
 - eager load workspace :owner when presenting non activity_stream workspace
 - only Events::NoteOnWorkfile and Events::WorkfileResult can have :notes_work_file_results,
   so reduce n+1 query occurrence to these events without eager loading
[#70124412] Eager load activity stream associations

 - Notably, eager load activity associations for entity_type specific activity queries
 - Eliminates many n+1 queries for comments
[#70124412] Eager load import :destination_dataset

  - Eager load destination dataset
  - Only check source_id before source.try(:name), so we only try to load source
     if there is a source id. Even if the dataset has been deleted, .try(:name) is safe.
[#69775976] Improve workfile syntax highlighting

 - Include display and/or syntax highlighting for r, rb, py, pig, js, and md files
 - dry up some isSql workfile checks
[#70199988] Backport Backbone removal of automatic url -> model attachment from options

 - Backbone 1.0 introduced automatic attachment of url to a model from options.
   It was promptly removed in 1.1.0, but 1.1.x introduces several more breaking changes
   (no attachment of options to Views and Collection#add,set,reset,remove
   return the changed model or list of models instead of the collection itself).
Minor spelling/style updates
Backbone 1.0 implements Collection#findWhere

 - no need for ours anymore