Feature/grid infinite scrolling

https://www.pivotaltracker.com/story/show/54756722

By adding "scroll=true, paged=true" to the Tent.JqGrid, the grid can be paged vertically using the right scrollbar.
Scrollbar dragging is supported. When dragging stops for a number of milliseconds, new page data will be loaded if required.

General Cleanup:
- Removing grid_filtering_support.coffee and grid_paging_support.coffee, as they are no longer used.
- Renaming of some variables in 1pr_jquery.jqGrid.src.js for clarity

__General Requirements__
- [x] Pull Request contains full description of changes
- [x] Link to the Pivotal Tracker story
- [x] Rebased against latest master branch
- [x] There are no `-1` code reviews (can only be overridden by Kyle)

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__Coding Standards__
- [x] Style guidelines are followed, code has been formatted
- [x] Code follows idiomatic language paradigms

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__Testing__
- [x] Test coverage has not decreased
- [x] There is no performance degradation
- [x] All appropriate automated tests are present
- [x] Appropriate seed data exists


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__Documentation__
- [x] Major design decisions have been documented on the wiki
- [x] Deployment impact (changes required for new services, configuration, etc.)
- [x] documentation links from Pull Request

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__UI/UX__
- [x] applicable (UI/UX has been changed)
- [x] reviewed for usability and design
- [x] functions on 1024*768 browser size
- [x] works on IE8

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__Shared Project / Dependencies__
- [x] Reviewed by Architect
- [x] API changes to shared components documented on wiki
- [x] 3rd-party library introduced:
- [x] explanation for updating a project dependency (e.g. 'latest version fixes a bug')

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__Defect__
- [x] Feature or defect resolution has been manually tested and meets all requirements of the underlying story
- [x] Seed data sufficient to satisfy testing resolution of defect
- [x] Root cause analysis provided