Quotation marks should be internationalized

[huji]

Currently, if quotation marks are used in a piece of text (like a comment) they are converted to a “ for the starting and a ” for the closing quotation mark. In non-Latin languages (like Arabic and Persian) other marks should be used. There should be a way to internationalize them.

[huji]

Another example: Default theme uses something like this to show the tags of a post:

the_tags('Tags: ', ', ', '<br />'

This should be internationalized in two ways:
1) Instead of hard coded phrase "Tags: ", an i18ned version should be used like this:

the_tags(('Tags: ','kubrick'), ', ', '<br />')

(Default_fa theme uses this method, at the moment).

2) Furhther than the above, the comma should be i18ned:

the_tags(('Tags: ','kubrick'), $theComma, '<br />')

And the global variable $theComma should be set as ", " by default, and get overridden for special langauges using their .mo and .op files.

[ryan]

See #7164