Use an explicit filename when running wget

Without this, I found that wget (on Webfaction, at least), chose
a filename like `1.7.4`, which broke the rest of the script.
Ask the user whether they want to open their browser.

I ran this from an ssh console on a server, so the `heroku open` command
failed.

Small grammar fix, too :-)
Add env var for heroku php

Without this, I found that the "update feeds" job failed with:

'...libmcrypt.so.4: cannot open shared object file: No such file or directory'

Credit to http://stackoverflow.com/questions/10614454/php-heroku-background-workers
Merge pull request #1 from mozz100/master

Some tiny changes for first-timers and a heroku env var; thanks to mozz100 for this commit