Callback moved to Utils/old
added Nette\Utils\Callback, static replacement of Nette\Callback

Object Nette\Callback can be replaced with native Closure.
removed usage of Nette\Callback in framework
ObjectMixin: feature "getting public methods as Closure" returns object Closure instead of Nette\Callback (BC break)
whitespace, used common (and verbose) indentation in switch statements
typos
added Nette\Utils\FileSystem
FileSystem: copy() and rename() throws exception when destination exists
typos
tests: updated tests
Strings::findPrefix: fixed bug
LimitedScope: removed workaround for bug #48912 in PHP 5.3.0
Revert "LimitedScope::load allows load script once [Closes nette/nette#321]"

This reverts commit 6ae3334dea4b. Issue nette/nette#321 was solved by 917b3819
LimitedScope: fixed compatibility
SafeStream: added support for ftruncate
Database: added support DateTimeImmutable & DateTimeInterface [Closes nette/nette#1216]
Validators: tests for IDN email addresses
typo
DateTime: use static instead of self
Json: do not use JSON_BIGINT_AS_STRING with PECL JSON-C [Closes nette/nette#1244]

If JSON_BIGINT_AS_STRING option is used for json_decode(), warning arises on 64bit systems.
https://github.com/remicollet/pecl-json-c/blob/3c778e58b20ed517edb27a3937966c4b0154ab21/json.c#L977