Refactoring work to add in Workflow UUIDs
Fixing some small bugs to get the code to work
Merge 'recent jobs' view from PR466/467. Work in progress.
Remove extra p tag from jobs admin.
Fix (old) bug causing Jobs grid to display even when there were no jobs to show in it.  Issue was 'jobs' (and the new recent_jobs) was actually a Query object and not an empty list of results, causing 'if jobs' to evaluate True regardless of whether or not there were jobs.
Clarify wording, explain cutoff.  Add headers to better segment the page and prevent confusion between the two grids.
Merge.
Merged in kellrott/galaxy-farm/workflow-uuid (pull request #471)

Workflow UUIDs
UI, Dataset choice control: add DatasetChoiceModal for choosing single or multiple datasets, add DatasetChoice and MultiDatasetChoice for displaying and activating selection modal from within a page; correct lookup of galaxy_config in dataset-model; add ListPanel for displaying collections of ListViews; add DatasetListPanel for displaying collections of generic datasets; add default no-op localizer (_l) to ui.js until that file is AMD; factor out icon-btn.less from history.less; remove make_popup_menus in default expandable behaviors
(add packed scripts)
UI, Paired collection creator: refactoring of paired HTML and fixes to draggable partition, add brush selection to unpaired
Reduce workflow step state and module population duplication.
Move all operations prior to workflow invocation (and a few other places state and modules are used) relating to populating the non-persistent attributes of `WorkflowStep`s (e.g. module, state, upgrade_messages, and input_connections_by_name) into a single function on a new class.

This should fix a couple of small errors as well - input_connections_by_name was being mis-calculated in a few places (though potentially never used down those roads) and some error handling code in the workflow editor template was expecting step.module to be populated with something (even if None) and it was not always.