indexed-db. Checkouts from previous backed out work.

indexed-db.js: from 862ba11a
indexed-db.md: from 192d5a3642

Both files moved into correct new locations
Bug 833042 - Consuming promises first example doesn't make sense
Bug 832401: Put the new context-menu separator before the old one.
Expose IndexedDb api (bug 786688)

Compared to previous commit (862ba11a):

* remove db prefixing
* per-addon security principal
* all strings changed to double quotes
* freeze `exports.indexedDB`
  - (heritage.extend, rather than `object.Create`)
  - includes test
* use `addon://` fake scheme in principal
* makeFunc replaced with `bind`
* sanitized "indexeddb" uri for principal

Risks:

* will make data created using previous sdk INACESSIBLE
  (unless they take effort to find the data and export it,
  which is non-trivial)
* relying on `sanitize(packageID)` might make data INACCESSIBLE in the
  future if we change how `packageID` is derived.

Doc updates:

* indexedDB docs reflect openForPrinciple
* external example usage
* changed 'aside' to reflect current bug status on protocols, principle
* removed outdated notes on Database Naming

All tests pass.
Merge pull request #719 from gregglind/bug786688indexeddb

Expose IndexedDb api (bug 786688) r=@ochameau
Bug 836061: Specify the radix for octal parseInt calls. r=ochemeau
branched off 1.14, master is now destined to become 1.15
Bug 836419: Don't log exceptions as a test failure in parseable output to match verbose output.
Bug 836419: Don't log the expected exception in the emitLoop test.
Bug 836318: Items in submenus default to visible rather than using the PageContext.
Bug 816611: Remove the explicit timeout from the widget tests.
Merge pull request #752 from Mossop/bug816611

Bug 816611: Remove the explicit timeout from the widget tests. r=Kwierso
Bug 836580: Turn on httpd debug output when in verbose or parseable modes.
Merge pull request #746 from Mossop/bug832401

Bug 832401: Put the new context-menu separator before the old one. r=@erikvold
Merge pull request #753 from Mossop/bug836580

Bug 836580: Turn on httpd debug output when in verbose or parseable modes. r=Kwierso
Merge pull request #751 from Mossop/bug836318

Bug 836318: Items in submenus default to visible rather than using the PageContext r=@erikvold
Bug 836580: Turn on httpd logging for the request tests.
Merge pull request #755 from Mossop/bug836580_2

Bug 836580: Turn on httpd logging for the request tests. r=Kwierso
Merge pull request #749 from Mossop/bug836419

Bug 836419: Fix a phantom test failure in parseable output. r=ochameau
Bug 836580: Use the profile directory for the temporary test files.