Fix up email changes
Merge branch 'master' of https://github.com/joomla/joomla-platform into emailvalidation

Conflicts:
	media/system/js/validate.js
Allowing JDatabaseDriver::quote to take an array of strings.

If supplied with an array of strings, the quote method will return an
array of quoted strings.
Documentation for the escape and quote methods added.
Unit test updated.
Made the type checking on the text for quoting less strict.
Adding destroy() method to JImage

Now with 100% MORE TESTS

Adding the ability for the code to self execute and automatically destroy the image handle

adding destroy() method to crop and resize as well

Fix UT Failures

Moving the destroy method

Fix CS Errors
Fix bug in `JDataSet` when unsetting within a foreach loop.

The use of `offsetUnset` on the current iterator point within a foreach
loop was causing unpredictable results. If the current pointer is being
unset, the pointer is moved back one unless it's the first element of
the array, in which case the pointer is set to false. The `next` method
then checks for this special case of `false` and rolls to be 'first'
element of the array (which would have been the 'next' one if the offset
had not been unset).

This PR also adds a new `clear` method to reset the contents of the set,
and a `keys` method that works in a similar way to the `array_keys`
function.

Tests and documentation have been updated accordingly.
Improve documentation for the JInputFiles class.
Add some new tests for quote.
Add a missing language format to JInput docs.
Merge pull request #1731 from eddieajau/input

Improved documentation for the JInputFiles class.
Merge pull request #1718 from eddieajau/database

Allowing JDatabaseDriver::quote to take an array of strings.
Merge pull request #1730 from eddieajau/data

Fix bug in `JDataSet` when unsetting within a foreach loop.
Fix and expand JDatabaseQuery tests.

Fixed mocking of the quote method in TestMockDatabaseDriver to allow for
an array of strings to be quoted.
Fixed a bug in JDatabaseQuery->quote that escaped strings before sending
them to the JDatabaseDriver->quote method ($escape argument was not
being honoured).
Added the escape method to TestMockDatabaseDriver.
Added covers to and improved code coverage of the JDatabaseQuery class.
Change registerPrefix and registerNamespace for LIFO
Merge pull request #1739 from dongilbert/JLoader_registerPrefix

Change registerPrefix and registerNamespace to LIFO
Improve docblock, add type hinting and default null to JSession::getInstance.
Small array merging optimization
Merge pull request #1740 from elinw/sessionfix

Improve docblock, add type hinting and default null to JSession::getInst...
Add some new tests, clean up some others.
Add a CONTRIBUTING file to the repo