use apt-fast if installed, multiple argument handling and more

[zeroxoneafour]

Changes made in this PR -

• Use apt-fast instead of apt-get if it's installed. If it's not installed, go back to apt-get.
• Updated the search function, which seemingly wasn't completed yet
• Many more things work with multiple arguments
• Check for arguments if a function requires them

[zeroxoneafour]

Also fixes #13

[bagnacauda]

I would personally leave less, but use the -R option to display colors. Or, maybe even better, replace it with the environment variable PAGER so it is configurable by the user.