v0.43.0

Most relevant commits:

• compiler/parser: simplify and fix function parameters parsing
• compiler/checker: fix importing a precompiled pkg from imported file
• compiler/parser: make struct parsing conform to spec and Go compiler
• compiler/checker: fix 'imported and not used' error on precompiled pkgs
• compiler/ast/astutil: allow CloneNode to clone a StructType node
• compiler/lexer: fix column numbers lexing raw strings
• compiler/parser: fix parsing of non-terminated expressions
• compiler: support tags in struct type declarations
• compiler/checker: support struct declarations with implicit fields
• scriggo, compiler: pass package loader as option
• scripts: pass package loader as option
• compiler/parser: fix position of the identifier of 'import' declaration
• compiler/lexer: trim "data-" prefix checking if attribute contains URL
• compiler/lexer: trim namespace checking if attribute contains URL
• compiler/lexer: treat "xmlns" attributes as contain URL
• compiler/lexer: treat 'src', 'url', 'uri' in attributes as contain URL
• compiler/lexer: make tag name scanning more permissive
• compiler/emitter: allow indirect registers in lhs of for range statement