usr.bin: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

bintrans: replace the quoted printable encoder/decoder

Replace the quoted printable code with one that respects RFC2045
Add tests about this parsers and encoders, using examples from the
wikipedia page.

Reviewed by: pstef
Differential Revision: https://reviews.freebsd.org/D36314

Add a quoted-printable encoder/decoder

As an example:
printf 'We don=27t know what to do with other=20worlds.=0D=0A' \
| bintrans qp -u

Differential Revision: https://reviews.freebsd.org/D34933

Reviewed by: debdrup (manpage)

Add the base64 command using b64encode and b64decode

Various scripts expect the base64 command to be present. We've had the
code and it's been exposed as b64encode/b64decode, but it wasn't widely
known under these names and the syntax is much different.

Reviewed by: delphij
Differential Revision: https://reviews.freebsd.org/D32945

bintrans: move files to a new directory

And reflect the change in various places.