v0.3 prerelease

[rrevenantt]

Current list of possible improvements for next version

• workaround to use stable rust(fixes Not building anymore on new versions  #46, fixes unknown feature raw #34)
• workaround for visitors to return data (fixes Return Types for Visitors #23, fixes Visitor's return type #22)
• fixes Generating Listenable::exit #20
• remove proc macro dependencies
• CI to auto publish on new cargo.toml version
• Allow storing lifetimed user data in parser(fixes [Feature Request] add 'input lifetime parameter to ParserExt defination #45)
• limit inline bit operations to 32bits (fixes Integer overflow w/ generated lexer #47)
• merge Check the returned value of self.get_context() before unwrap it. #38 (closes Check the returned value of self.get_context() before unwrap it. #38)
• move to once_cell completely
• rustfmt in antlr tool
• make Node and associated type in visitors
• bulk import for context extension traits
• move child methods on parserRuleContext to extention trait
• intradoc links
• move benches to repository
• LexerAtnSimulator position tracking customization
• Lexer position tracking customization
• thread local DFA(questionable because of quite slow threadlocals in rust)
• arena allocation for tree nodes/ generic(gat) trees
• use less Deref as some inheritance hack
• tree utils
• features
• stateful lexer test
• better downcasting
• options for customizing downcast bounds
• token stream rewriter
• some doctests + dummy parser for them
• actual examples
• normal visitor example/docs
• string interner test/example
• figure out base class api replacement
• rustfmt import config
• draft upstream PR
• add recursion limit
• test custom errors
• add fuzzer tests