Description:
------------
HttpQueryString class translates '.' in params to '_'

This behavior (which is obviously being copied from parse_str) makes sense when parse_str copies parameter names into the global variable scope, but it is *invalid behavior*.  "." is a completely acceptable character for parameter names to include.

A "next generation" module shouldn't copy the bad behaviors of the function it's replacing.

Test script:
---------------
$query = 'bar.baz=blah&utm_source=google&utm_campaign=somethingelse&blat';

$foo = new HttpQueryString(false, $query);

print_r($foo->toArray());

echo $foo->toString();

Expected result:
----------------
Array
(
    [bar.baz] => blah
    [utm_source] => google
    [utm_campaign] => somethingelse
    [blat] => 
)
bar.baz=blah&utm_source=google&utm_campaign=somethingelse&blat=

Actual result:
--------------
Array
(
    [bar_baz] => blah
    [utm_source] => google
    [utm_campaign] => somethingelse
    [blat] => 
)
bar_baz=blah&utm_source=google&utm_campaign=somethingelse&blat=