add explore() function

- optimize and replace tree() function
- moved to helpers
- delete utilities functions file
Homepage default behavior : cache by default
Response : add Vary: Accept-Encoding header
Implement http_response_code for PHP < 5.4
git allow templates, controllers, models
Extended exceptions : bug fix getData method
Improve Response class
Mail class (v2.4)

Add exception for invalid From email
Configuration informations moved to options file
Init file : bug fix extended exceptions classes call
Init : json function exists in PHP 5.3+
Bug fix Request class : URI parameters had always first parameter value
helpers : reverse parameters order

Search $path in $array is more logical
Compatibility namespace replaced by UTF8

This is shorter and more development friendly (and logical too)
Request class restructuration

- parameter() method now use dot notation to get array’s value
- implement header() method
- secured() method renamed as secure() (misspelling mistake)
- implement format() method
- method parameter implement $verify parameter
- implement uri() method in other classes
Core restructuration

Global :
- Remove SYSTEM_DOMAIN_ALIAS
Cookie class :
- Secured request always send crypted cookies (even if $crypt = false)
- Set method allow to define action domain
- Set cookie : no duration limit by default
- method all() implemented (return all cookies)
- method clean() implemented (delete all cookies)
Session :
- Session started in the init file
- languages and user id now generated in the index.php file
- Removed predefined login/logout functions
- clean() method implemented
- Define session information now has $persistent parameter (save
session parameter value in a crypted cookie; use cookie’s class to get
it back).
- implement session clean() (destroy all session informations)
Helpers :
- array_value : implement default value
- array_set : add a value with a dot path
- array_unset : delete and index in a an array with a dot path
Request :
- implement segment() method (get uri part)
- move some request info to functions
Extended Exceptions : implement setCallFromTrace() method

Redefine $file and $line attributes from $trace
Mail class (v2.5) : improve with extended exception

Now use ExtendedExceptions->setCallFromTrace()
Console : improve logs registration

Also move register_shutdown_function() in the option file
Helpers : implement is_cli() function