Make `Charset` a builder.

[zhiburt]

Now we had to call Charset and TabSize to correctly handle arbitrarily data.
Which at the end of the day does 2 allocations....and whole string pass through 2 times.
Which is quite bad...

We shall move Tabsize logic into Charset and make the foremost use Builder pattern.
So we will set what changes we need to do them all at once.
Specifically a tabsize setting (currently I have 1 in mind) but likely we can came up with more convenient things.

tabled/tabled/src/settings/formatting/tab_size.rs

Lines 46 to 62 in 91fdedb

	impl<R, D, C> TableOption<R, C, D> for TabSize
	where
	R: Records + ExactRecords + RecordsMut<String> + PeekableRecords,
	{
	fn change(self, records: &mut R, _: &mut C, _: &mut D) {
	let tab_size = self.0;
	for row in 0..records.count_rows() {
	for col in 0..records.count_columns() {
	let pos = pos(row, col);
	let text = records.get_text(pos);
	let text = text.replace('\t', &" ".repeat(tab_size));
	records.set(pos, text);
	}
	}
	}
	}

tabled/tabled/src/settings/formatting/charset.rs

Line 133 in 91fdedb

text.replace(|c| c != '\n' && c < ' ', "")