Release 2.2.0

• FIX: Allow backreference as first arg of implicit call
• FIX: Exclude ? and ! from class/instance/global variable name
• FIX: Fix parsing of hashes containing assignments
• FIX: Parse aliases of unary operators and methods named as keywords
• FIX: Parse alias of keyword-like method to assignment method
• FIX: Parse alias/undef of assignment methods
• FIX: Parse backtick as method name
• FIX: Parse class/module definition in dynamic class/module
• FIX: Parse def !
• FIX: Parse def foo::bar
• FIX: Parse foo(<<FOO)
• FIX: Parse for ... do and while ... do
• FIX: Parse global variables beginning with $_
• FIX: Parse keywords/operators as method names for ::
• FIX: Parse LINE constant
• FIX: Parse more percent strings
• FIX: Parse more regexes
• FIX: Parse more stabby procs without parentheses
• FIX: Parse multiple parameters set to the same default value
• FIX: Parse parentheses-less stabby proc with keyword arg
• FIX: Parse undef of methods with special names
• FIX: Parse unless ... then
• FIX: Parse variable names starting with extended ASCII characters
• FIX: Raise SyntaxError for def ====
• FIX: Raise syntax error for def +@.foo
• FIX: Tokenize unterminated ternary at EOF
• FIX: Use lower precedence for block pass