Rename BrowserID-Version header to BrowserID-git-sha

fixes #3125
Simplify the storage.js interface

* Remove setLoggedIn and getLoggedIn
* Remove signInEmail namespace

Data is now handled by the storage.site.set/get functions with approprite namespace keys. This is to make where this info is stored consistent with other site specific info.
Fix button width in "Is this your computer" not keeping up with screen resize.

jQuery changed the way to remove a manually set CSS style. We did not keep up when we updated jQuery. Now we do.

fixes #2066
Fix check_primary_support to read responses
Convert the last remaining "BrowserID-Version"s to "BrowserID-git-sha"s
Add KPI load testing docs

    These used to live at https://gist.github.com/kparlante/5054439/
    and might be useful, so let's add 'em to the docs folder
Explicitly list default for parallel execution of tests
Put the default for -p in the right place.
Merge pull request #3204 from karlht/issue3174

Explicitly list default for parallel execution of tests
Merge pull request #3203 from 6a68/add_load_testing_docs

Add KPI load testing docs

Thanks @6a68!
Merge pull request #3183 from mozilla/issue_2066_button_width

Fix button width in "Is this your computer" not keeping up with screen resize.
Dynamically shrink footer text to fit on one line.

    Fixes #3129.
Merge pull request #3149 from mozilla/issue_3125_version_header_name

Rename BrowserID-Version header to BrowserID-git-sha
builds on get_assertion to post to a verifier and check the response; useful for aws and other buildout
Fix the ugly npm install errors.

Only install the automation-tests deps if AUTOMATION_TESTS=true is defined on the command line.

fixes #3160
Merge pull request #3207 from mozilla/issue_3160_npm_install

Fix the ugly npm install errors.
Add "white-space: nowrap" to allow @6a68's fix to work properly.
Merge branch 'issue_3129_shrink_footer' into dev
Add tabindex attributes to the TOS/PP links.

Allows users to tab directly from the email/password field to the submit button.

fixes #3079
set agent:false for requests