devel/okteta: Update to 0.26.13

Add LICENSE (dual licensed GPLv2 or GPLv3 only)

Changes since 0.26.12:

• Improved: translations
• Improved: Decoding table now displays some control chars as escaped terms
• Improved: Decoding table now supports editing some chars as escaped terms
• Improved: Structures tool now feeds some chars as escaped terms to editor
• Improved: CMake Unity builds now possible
• Fixed: Structures tool stored edited primitive array elements on bad offset
• Fixed: Structures tool now displays chars only as the supported 7-bit ASCII