Upgrade path from i18n_icon_* to languageicons_*

Here's a complete .install - including a languageicons_uninstall() for removing the site variables when removing the module.

Eh. Let's try that again.

And here's a small update, making it call variable_get() only once (per variable to convert) and fixing a bug due to not following up on the if (...) with {. :$

Added a bit of logic to make the update reset the ..._path variable if it was using the default one (drupal_get_path('module', 'i18n') .'/flags/*.png'), so that Drupal/the module will use the new location for the files. I'm not sure about this part of the update though, so feedback would be appreciated. :)

And here's my final bid, which I have actually tested and am therefore rather confident that it works. Now I just need to know whether to drop the _path if it is == drupal_get_path('module', 'i18n') .'/flags/*.png' or not (the current behaviour is that it does drop it (instead of converting it)).

And here's a wee update. This one will only set languageicons_* if they're not already set - if they are, it'll just delete the old i18n_icon_* variable. A bit more logic about the *_path variable was also added.

I split the languageicons_uninstall() off into its own issue: #294819: Remove site variables in languageicons_uninstall()

Also, since that one has already been committed: a re-roll, now as an actual patch!

Alright, excellent - it's been committed. :)