Proposed Update UTS #18, Unicode Regular Expressions

UTS #18, Unicode Regular Expressions, is being updated to bring it into alignment with Unicode 6.3. Two new bidi-related properties introduced in Unicode 6.3 for the Unicode Bidirectional Algorithm are being added. In addition, the discussion of script extensions is being extended and clarified.

The proposed update document is now available for review and comment. See Public Review Issue #252.