Allow args in i18n

i18n function should be able to handle args, for example when a file name is required. Something like: `There's already a file named %{name}%`. In some languages it could be written differently so I added this to the core. Now language files could contain something like: 
```php
$lang["There's already a file named %{name}%"] = "Esiste gi&agrave; un file chiamato %{name}%";
```
Small fix for some php configurations

Some php configurations handle `{$var}` in string as the var itself
The lang array can be empty in english

Codiad is default in english, so we don't need to "translate" from english to english :P
Merge pull request #437 from newsocialifecom/master

Fixes in translations