* Update caffeinate.md
Add -d command to prevent display from sleeping (most useful one to know imo).
Remove `-s` because it functions like `-i` except that it only works while on AC power
Better description for `-i`
* Add colon to end of example
Fixes#310
Some files had no newlines, some had 1 newline and some more than 1 newline.
Normalize them all to have only 1 newline at the end of all files.