Build: Update tested browsers
Build: update dependencies
Build: Append the date to local build names

All local runs have been so far appearing under a build called "local run",
supposedly running for 121 days now and failing. Separating runs helps with
the organization and allows to see the result of a particular run at a glance.
Build: bring Opera 12.16 back to the list

Closes #258
Build: remove needless comment from grunt config
Build: re-arrange browser definitions
Build: add Opera 11.6 to the browser list
Build: fix "grunt start" command
Core: Drop strundefined variable

Closes gh-276
Core: Optimize `indexOf` usage

Use a simple `for`-loop as it is faster than native function.

Closes gh-280
Build: update Chrome 35/36 to 36/37 in tests
Build: Update Firefox 30/31 to 31/32 and Opera 22/23 to 23/24 in tests
Selector: [attr~=val] should recognize all whitespace as delimiters

Fixes jQuery #15233
Selector: Support DocumentFragment context

Semver minor bump for new functionality

Fixes #284
Selector: Never clobber preexisting results
Core: Make expando a valid identifier for improved performance

Thanks @jbedard

Ref jQuery #14839 comment 13
Ref chromium issue 378607
Build: Move tests out of "build" task and back to "default"

Useful for selective targets (e.g., `grunt build karma:phantom karma:oldIe`)

Ref 095fc5ddcb145f849b7d92f0f393a52d751b27e0
Build: update karma plugin for QUnit and QUnit itself

Ref karma-runner/karma-qunit#17
Build: update browserstack launchers

* Replace "Motorola Droid 4" to "Motorola Droid Razr"
  since support for it was dropped

* Update Chrome and Firefox versions

* Add iOS 8, but don't use it, since currently it's unstable on browserstack
Build: use latest chrome and firefox versions for tests

Even though some of the browserstack API's says it doesn't support them.
We believe it does.