Bug fixes and code improvements

Please review your translations after new export because the fixes we have applied may cause some of your translatable strings become untranslated again. We encourages you to store the translation files in Git to be able to rollback in case anything goes wrong.

Changelog:

• (bug) Strings containing round brackets are truncated improperly #45 (thanks to @kkomelin, @kohlerdominik)
• (bug) Undetected strings if "key"-argument starts on new line #57 (thanks to @kohlerdominik, @kkomelin)
• (bug) Fix some parsing issues #52 (thanks to @Hannoma, @kohlerdominik, @kkomelin)
• (internal) Revised Regex Pattern for more accurate matches #71 (thanks to @kohlerdominik)
• (internal) Refactored a few deprecated code pieces (thanks to @kkomelin)