Support bi-directional text and languages

[heinezen]

Not all languages are left-to-right (LTR), e.g. Arabic, Hebrew and eastern writing systems. These are typically written right-to-left (RTL), but english words are usually LTR if they occur in the text (hence bi-directional).

Example: اليمين (LTR) المستخدم

Unicode supports markers for text that tell when a text switches from RTL to LTR and back. In addition to supporting the strings, some additional features should be made

• correctly implement line breaks and display of characters
• Offer a UI preset that is RTL (e.g. minimap on the left, command buttons on the right). Some UI elements should be provided as a "flipped" version

[TheJJ]

I think we should rely on Qt's features for that. Somewhat related to #107 because only they will need this feature.