Fix compiler crashes and improve return statements.

[water111]

• Fix crash when non-ascii characters are entered in the REPL or a source file.
• Fix crash when an empty cond statement is encountered. It is now an error.
• GOAL kernel will detect when you try to run something with a stack in the scratchpad and move it to a fake scratchpad stack.
• return statements in the decompiler will look nicer now.
• Fix crashes in some uses of forward declared types
• Allow decompiling arrays containing symbols

[coveralls]

Pull Request Test Coverage Report for Build 984615165

• 28 of 54 (51.85%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 69.256%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
decompiler/IR2/FormExpressionAnalysis.cpp	3	4	75.0%
decompiler/util/data_decompile.cpp	0	2	0.0%
goalc/compiler/SymbolInfo.h	0	3	0.0%
common/goos/Reader.cpp	20	28	71.43%
goalc/compiler/compilation/CompilerControl.cpp	0	12	0.0%

Totals
Change from base Build 984603576:	-0.01%
Covered Lines:	37030
Relevant Lines:	53468

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💛 - Coveralls