Added youtube-dl cheatsheet
fixing typo in cheat git
added new examples for find
added examples for pdftk (manipulating pdf files)
added example for the gs command (reduce pdf file)
corrected typo for a better management of files with space in their name
To copy a key to a remote host on a non-standard port with non-standard ssh key
remove ssh-copy-id
add ssh on a non-standard port
Cheatsheets added

 - apk: Alpine Linux package manager
 - gcc: GNU C Compiler
 - grep: Pattern matcher in files or pipes
 - vim: Vi IMproved
Adding less cheat sheet
Adding additional ssh-keygen command examples
Adding additional ssh-keygen command examples
Added mysqdump backup and restore and basic connection
Introduce DEFAULT_CHEAT_DIR environment variable

Now ~/.cheat can be overridden
Add -d/--cheat_directories option to list directories containing cheatsheets
Add zsh cheats completions
Install zsh completions
Remove odd new line
Add note about DEFAULT_CHEAT_DIR to the README file