Add option to use numbers or given literals for dissection

[phun-ky]

For example, if I wanted to use numbers:

speccer({numbers: true});

This should be behind an option tbh.

Or given literals, like japanese:

window.SPECCER_LITERALS = [あ,い,う,え,お,か,き,く,け,こ,さ,し,す,せ,そ,た,ち,つ,て,と,な,に,ぬ,ね,の,は,ひ,ふ,へ,ほ,ま,み,む,め,も,や,ゆ,よ,ら,り,る,れ,ろ,わ,を];
speccer();

[phun-ky]

First release of this feature should be by custom literals only, so if someone wants numbers, use the literals array.