Import scripts with scene headings in other languages

Script import now recognises scene headings written in several other languages, so these scripts split into scenes and frames correctly.

Supported headings include:

• German: INNEN, AUSSEN
• Polish: WN., PL.
• Swedish: INTERIÖR, EXTERIÖR
• Norwegian: EKST.
• Finnish: SIS., ULK.
• Russian: ИНТ., НАТ., ЭКСТ.

Character names written in non-Latin capitals, such as Cyrillic, are also picked up.