Previously we unconditionally appended a newline to all clipboard
contents, which ended up corrupting binary files like PNG images when
using shell redirection (e.g., `wl-paste > file.png`). Now we
intelligently (in quotes) detect content type via MIME type and only
append newlines to text-based content such as `text/*`,
`application/json` and so on. Binary data on another hand is written
exactly as it is. Falls back to UTF-8 validation when MIME type is
unavailable.
On paper this is also fully backwards compatible; text content still
gets newline by default *unless* the `--no-newline` flag is used.
Fixes#52
Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I8b1e6f7013d081150be761820cafd1926a6a6964
