Allow specifying a text encoding for text in a binary template

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Something along these lines, perhaps:

char utf16_text[x] <encoding=UTF-16LE>;

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Some possible syntaxes for this:

Something like 010 Editor: char text[100] <encoding="UTF16-LE">
A weird cross of 010 Editor and C++ templates: char<encoding="UTF-16LE"> text[100];
Something akin to GCC attributes: char text[100] encoding("UTF-16LE"); or char text[100] attribute(encoding="UTF-16");

And some other things that might want to be covered by the same syntax:

• Endianness (overriding the global flag)
• Instruction set for disassembly/code type
• Alignment

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Implemented in 8c7b955.