Add signature for Ubiquiti firmware additional data

Update deps.sh

Added Toshiba SSD Firmware Update magic.

add UNIQUE_PATH_DELIMITER to mount command

Added lz4 and zstd comporessions to squashfs.

Improve help output for --dd

travis: Update Python versions

Stop testing on unsupported Python 3.3

Drop Python 3.3 which isn't available anymore, add python 3.7 and 3.8 instead.

Make it clear that ext/cmd are optional and that the type can be a regular
expression.

Newest squashfs in upstream has supported LZ4 (5) and ZSTD
(6) as compression algorithms. However, they didn't exist in binwalk's
current magic library. This commit added the magic values so that squashfs images
compressed by these algorithms could be successfully identified.

Ref:
https://github.com/torvalds/linux/blob/master/fs/squashfs/squashfs_fs.h
https://github.com/file/file/blob/master/magic/Magdir/filesystems

Add signature/decryption support for PGP RSA encrypted session key

Added PKCS#7 Object signature

deps.sh: use new upstream cramfs-tools

Update binarch with AArch64 instructions

Remove conflicting signature for flattened device trees

make API example python3 compliant

Adding version into sdist

Fixed issue with next_target_file being unicode and causing an exception

"/etc/os-release" is more common than "/etc/lsb-release"
source: https://gist.github.com/natefoo/814c5bf936922dad97ff

Updated EXT signature to detect and skip to the end of the EXT image

`s/Not/not`

fix getting user's home dir