[0.2.0-unstable]

Added

Changelog
Example: JSON lexer + parser
ParseError::map_error_details: a more convenient function for changing error details
trailing + method version: a combinator similar to left, but allows the second parser to fail
was_parsed + method version: a combinator similar to optional that returns a boolean
ParseError::append_error and ParseError::prepend_error for more convenient error details modification

The functions left, recover, recover_default, right, and trailing no longer have the T: 'a constraint.

A new convention for error constructor functions has been established:
- First argument: details: &str, required on all constructors
- Second argument (if applicable): loc: Toks, not required of constructors for situations where no meaningful value can be provided (e.g., empty_input).
- All other arguments following these are specific to the type of error being constructed
Due to the above: the following constructor function arguments have changed:
- empty_input() is now empty_input(details: &str)
- unexpected_input(loc: Toks) is now unexpected_input(deatils: &str, loc: Toks)
- not_enough(loc: Toks, needed: usize, got: usize) is now not_enough(details: &str, loc: Toks, needed: usize, got: usize)
- other(cause: E, loc: Toks) is now other(details: &str, loc: Toks, cause: E)
Some other methods of ParseError were renamed to better suit Rust's conventions:
- ParseError::get_details renamed to ParseError::details
- ParseError::set_details renamed to ParseError::overwrite_details
- ParseError::get_loc renamed to ParseError::loc
- ParseError::get_loc_non_empty renamed to ParseError::loc_non_empty
Newly-named ParseError::details function returns &str instead of Option<&str>
Combinator error_details renamed to map_error_details