Replace FasterCSV with CSV in lib/benchmarking
vagrant can now see Markus folder on home machine
Rename shared example file to fix RSpec warning

If the name of a file under spec/support ends with `_spec.rb`, it will
be loaded first by the RSpec main command and then by `spec_helper.rb`,
causing an RSpec warning:

```
WARNING: Shared example group 'a criterion' has been previously defined
at:
  /home/su/code/Markus/spec/support/criterion_spec.rb:1
...and you are now defining it at:
  /home/su/code/Markus/spec/support/criterion_spec.rb:1
The new definition will overwrite the original one.
```

This patch fixes it by removing the `_spec` suffix. future Shared
example files should follow this rule.

Tested:
- rspec
Avoid n+1 queries when downloading all submissions

Lots of queries are redundant in the logic of downloading all
submissions and can be avoided by eagerly loading the associations.

Tested:
- rspec
- rake test:units
- rake test:functionals
Fix error when toggling "assign criteria"

The current JavaScript throws an error when clicking on the checkbox
"Assign Graders to Criteria" because it is trying to use an undefined
variable `element`, which should really be `this`.

Tested:
- local server
Replace readAttribute with getAttribute

`readAttribute` is a function monkey-patched by Prototype, so it won't
be available after removing Prototype. The standard function is
`getAttribute`.

Tested:
- local server
Refactor Grouping#add_tas

The `add_tas` method is just a special case of the new mass assign
method `assign_all_tas`.

Tested:
- rspec
- rake test:units
- rake test:functionals
Replace dataset and ensure parseInt have radices
Merge pull request #1651 from zhangsu/readAttribute

Replace readAttribute with getAttribute
Merge pull request #1652 from arkon/js-dataset

Replace dataset and ensure parseInt have radices
Merge pull request #1650 from zhangsu/assign_grader_criteria_error

Fix error when toggling "assign criteria"
Merge pull request #1649 from zhangsu/add_tas

Refactor Grouping#add_tas
Merge branch 'rspec_warning' of https://github.com/zhangsu/Markus into rspec_warning
Merge branch 'replace-fastercsv-benchmarking' of https://github.com/oneohtrix/Markus into replace-fastercsv-benchmarking
Fixed indentation for Hound
Merge pull request #1648 from zhangsu/download_all_submission_performance

Avoid n+1 queries when downloading all submissions
Merge pull request #1626 from munrocape/vagrant-ide

vagrant can now see Markus folder on home machine
Merge branch 'master' into MarkUsConfigurator2