Split Query operators into their own parameter

[hexus]

Queries can be written as such at the moment:

// Implying equality
$query->where('id', 1);

// Specifying an operator
$query->where('id >', 1);

Forcing the operator to be in the first parameter isn't pleasant. Follow Laravel and many other query builders in this regard.

// Implied equality
$query->where('id', 1);

// Specifying an operator
$query->where('id', '>', 1);

This is especially relevant for #54.