Merge pull request #4635 from lucasmichot/4.2-string-helper

[4.2] Support : add use ...\Str for string helpers
Added abstract method getDefaultDriver()

The driver() method calls getDefaultDriver(), but nothing in the class says it should be implemented.
Merge pull request #4707 from ibrasho/4.2

Added abstract method getDefaultDriver()
Fix punctuation.
Move method.
Merge pull request #4622 from adamgoose/4.2

Adding `$table->rememberToken()` method to schema builder
Working on documentation block.
Merge branch '4.2'
Merge pull request #4623 from Gufran/fix/dot-flatten-environment-variable-array

Fix/dot flatten environment variable array
Merge pull request #4615 from lucasmichot/4.2-flip

[4.2] Support : add flip to Collection
Work on comment.
Merge pull request #4547 from ambrella/4.2

[4.2] Gey keyName before instance can be translated into builder
Fix check.
Fixed before/after + date_format rules implementation

This fixes PR #3607 to provide missing features described on PR #1824 and PR #4699. Also rewrote testBeforeAndAfterWithFormat() tests.
Flagged exists as true when restoring the model
Throw an exception if a package is created without setting the author's email
Messed up Mailer (Introduced by 4.1 -> 4.2)

In 4.1 it was possible returning a count of sent emails from Mail::send().
In 4.2 you'll always get null returned. (Because Mail::send() is now returning the void method `sendSwiftMessage()`)

(`sendSwiftMessage()` was returning the count in  4.1 ...)


If that was intended the send method needs an update which I'm providing with this pull request.
Anyways I hope it was not and the send() method will return the count of sent emails again in future. (Was using this feature and liked it alot)
Add isPretending()
Added a patterns method to the router
Update readme.md contributing from 4.1 to 4.2

Small quick change of reference to keep readme.md current.