Constant `BASE64_MIME_PERMISSIVE`

pub const BASE64_MIME_PERMISSIVE: Encoding;

MIME base64 encoding without trailing bits check

This encoding is a static version of:

# use data_encoding::{Specification, BASE64_MIME_PERMISSIVE};
let mut spec = Specification::new();
spec.symbols.push_str("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
spec.padding = Some('=');
spec.wrap.width = 76;
spec.wrap.separator.push_str("\r\n");
spec.check_trailing_bits = false;
assert_eq!(BASE64_MIME_PERMISSIVE, spec.encoding().unwrap());

It does not exactly conform to RFC2045 because it does not print the header and does not ignore all characters.