ZeroCopy: All of `zero_copy::text`

[Zij-IT]

Here is a quick rundown of the changes:

• Additions:
  • zero_copy::text::whitespace
  • zero_copy::text::newline
  • zero_copy::text::digits
  • zero_copy::text::int
  • zero_copy::text::ident
  • zero_copy::text::keyword
  • zero_copy::Parser::repeated_slice
  • zero_copy::Parser::then_slice
  • zero_copy::sliced
  • zero_copy::sliced::RepeatedSlice
  • zero_copy::sliced::ThenSlice
  • zero_copy::text::Char::is_valid_ident_start
  • zero_copy::text::Char::is_valid_ident_continue
  • zero_copy::text::Char::is_digit
  • zero_copy::text::Char::is_zero

Here are some notes that I took while going through this:

• All of the parsers should have the same parsing capability as on the master branch, with slightly more return value flexibility.
• I wasn't really sure if the _slice methods that I added to Parser should be part of another trait or not.
• The user still has the same amount of flexibility with digits and int, though they may have to use an extra map. They both still work with Parser::from_str as they did on master!

If there is anything you find odd, or that looks like it could use improvement, please do let me know! Thanks in advance!

[Zij-IT]

This is just a bump, and something to let you know that I have done some cleanup of the branch since your last comment, and unless I find another bug, or you have any requests regarding this branch, I am done making commits to it :D