Fix colors with echo commands

[luca0N]

Use the -e option when using the echo command, as backslashes are not interpreted by default. This causes echo to print color escape codes as-is. This PR also replaces existing printf calls with echo for consistency.

[luca0N]

Some very minor things I've noticed:

• Some variables are printed with ${VARNAME} instead of $VARNAME. Should all instances of $VARNAME be replaced with ${VARNAME} for consistency?
• Some files end with a line break (\n), others don't (although all files have Unix line endings). Should we add an \n at the end of all files that don't already have it?

Again, these are minor issues that I decided not to push to this PR so that I could get feedback from Chris and the community, and also for the sake of keeping different submissions separate.

[ChrisTitusTech]

Thanks for these additions. I'd say lets standardize things and any inconsistencies can be a separate PR.