add \ quoting of characters in date format strings

[EricShulman]

Add support for use of \ to quote characters within date format strings so that, "\s\s" or "\m\m" can be used within the title param for <<newJournal>> to bypass date format replacement so that literal "ss" or "mm" can be included in the resulting tiddler title.

The code to do this is just one extra line added to the end of Date.prototype.formatString(), immediately before returning the result:

	t = t.replace(/\\/g,""); // strip backslashes used to quote formats
	return t;

[MartinBudden]

Fixed in changeset:5143