Improve Italian translations

Fixed some terms for better meaning and fitting in blocks
Added note about Run as Administrator for po2js
show selection color in textarea

Currently, you have no idea whether the text in "Export / Import" is
selected since the background is transparent.
Prestige shouldn't contain decimals

Corrects issue of Prestige containing decimals and Infinity

Closes #69
Update Chinese (Simplified) ISO 639-1 code
Correct Korean ISO 639-1 code.
Add underscore to language query string regex.
fix minor bugs in SM