`Mecha::SVR`, `Mecha::GVR`, `Mecha::UVR`

SVR: to set array value recursively
GVR: to get array value recursively
UVR: to unset array value recursively

Allow users to set, get and unset array data recursively using dot
notations.

### Example:

~~~ .php
$test = array();
Mecha::SVR($test, 'foo.bar.baz', 'test value');
~~~

### Results:

~~~ .php
$test = array(
'foo' => array(
'bar' => array(
'baz' => 'test value'
)
)
);
~~~

+ Another updates and code tidy up.