Abstract Syntax Tree Bugfixes and Improvements

[0x19]

• Full basic documentation of AST package
• Massive increase in code coverage for AST
• Overall code coverage fixes
• AST type descriptions and reference resolver works now much better
• Sources fixes

[coveralls]

Pull Request Test Coverage Report for Build 5885278661

• 634 of 746 (84.99%) changed or added relevant lines in 60 files are covered.
• 14 unchanged lines in 5 files lost coverage.
• Overall coverage increased (+7.2%) to 90.194%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ast/parameter.go	4	5	80.0%
sources.go	2	3	66.67%
ast/type_name.go	21	23	91.3%
ast/assignment.go	9	12	75.0%
ast/function_call.go	18	21	85.71%
ast/expression.go	6	10	60.0%
ast/expression_statement.go	0	4	0.0%
ast/reference.go	16	20	80.0%
ast/simple.go	0	4	0.0%
ast/tree.go	1	5	20.0%

Files with Coverage Reduction	New Missed Lines	%
ast/expression.go	1	88.16%
ast/expression_statement.go	1	58.82%
ast/simple.go	1	73.91%
ast/binary.go	2	97.39%
ast/reference.go	9	82.97%

Totals
Change from base Build 5868838432:	7.2%
Covered Lines:	11194
Relevant Lines:	12411

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💛 - Coveralls