Define date format in templates instead of index.php

[ArthurHoaro]

It allows theme creators to display dates the way they want to by playing with strftime function parameter.

cf #144

[ArthurHoaro]

@alexisju You're right, I need to look more at my IDE's log. Also I forgot the time in QRCode title.

I can do this

 {function="strftime('%c', htmlspecialchars($value.timestamp))"}

However, what is the point to htmlspecialchars a generated value such as timestamp? I'd like to get @nodiscc opinion on that.

[nodiscc]

Mind that the QR code will be moved as a plugin (part of #164)

[ArthurHoaro]

@alexisju comment has disappeared because it was probably a commit comment, and I rebased the commit. But the warning are gone, and I've removed htmlspecialchars on timestamps since they're not even user input.

@nodiscc it might be, but since the plugin system is not merged I've to assume the QRCode is still in core templates.

[nodiscc]

I've to assume the QRCode is still in core templates.

Sure.

[nodiscc]

Mostly ok to merge, @ArthurHoaro are you sure it's ok removing function linkdate2Locale() from index.php? Some templates in #163 may still use it.

Maybe it's safer to at least warn them, some time before this change?

[ArthurHoaro]

Well, that's actually the point of this PR: switch date formatting from index.php to templates. So yes, third party templates will have to make an update.

I don't see this as an issue because those themes support are in a separate milestone. But we can obviously warn them.

[nodiscc]

Merged in bec1870