Add ability to set background color for Free Text in the Editor

[r1bilski]

This closes #399

I often find the need to annotate elements on the screen, but it's difficult on backgrounds that aren't uniform. This adds ability to control background property on FreeText textbox.

I didn't know what is the process for translations so I just ran them through Google Translator. For es-AR and pt-PT I just used Spanish and Portuguese respectively.

[NickeManarin]

Thanks!