Simple EntityTag implementation.
std
- Add EntityTag::from_file_meta
in order to generate ETag using file's metadata.```rust use etag::EntityTag;
fn main() {
let mytag = EntityTag::strong("lolka");
let textetag = mytag.tostring();
let parsetag = textetag.parse::
assert!(my_tag.strong_eq(&parse_tag));
} ```