Version 3.0.0

Two breaking changes, both requiring a new major release:

• To conform with the ICU MessageFormat standard, escaping with a \ is no longer supported (so e.g. the strings \{ and \u0123 are now passed through without changes). Instead, use 'quotes' to escape, e.g. '{braces}'. To help deal with this change, we provide a codemod to handle the change for you.
• The optional parameter passed to a function is now a string, rather than an array of strings. So with e.g. {var, func, your param}, the parameter passed to func would be ' your param', including the leading space. As a consequence, we've also dropped the strictFunctionParams option.