Switch links to HTTPS/SSL/TLS and update them

[DerekTurtleRoe]

Adding HTTPS/SSL/TLS will make it more secure and private for all end-users, and most end-users who are new to the whole web browser thing probably don't understand encryption. Defaulting to that is probably best.

Update these links:
https://www.google.com/intl/en/chrome/browser/desktop/index.html
https://www.mozilla.org/en-US/firefox/
http://www.opera.com/computer

Further down towards the bottom:

http://windows.microsoft.com/en-us/internet-explorer/browser-ie

Twitter:
https://www.twitter.com/ejc

Credits page:
https://twitter.com/jubstuff
https://twitter.com/npantos
https://twitter.com/xkeeper
https://twitter.com/marek
https://twitter.com/rowakov

I'd submit a pull request, but my main PC is having internet troubles (I have AT&T 😱 ).