fill out stub credits section

+ spelling + ideated->created (idiomatic English)
don't re-use Homebrew's slogan

dunno what the best slogan is, but Homebrew probably prefers
ours to be different than theirs
Merge pull request #5 from rolandwalker/credits

fill out stub credits section
specify homedir-Applications folder
link Homebrew the first time we mention it

save the need to add extra text about how to install it
Merge pull request #8 from rolandwalker/link_homebrew

link Homebrew the first time we mention it
Merge pull request #7 from rolandwalker/home_app_folder

specify homedir-Applications folder
Don't change button text color on hover

Avoid contrast issues.
Add link to docs
Merge pull request #4 from rolandwalker/slogan

don't re-use Homebrew's slogan
switch to pretty quotes; trim trailing space