Change default keysize to 2048

If we're creating a self-signed certificate, we're obviously doing it for the encryption, not the validation.  Why, then, would we default to 1024-bit RSA when THE WHOLE WORLD is deprecating that and switching to higher security keys?!?  http://www.symantec.com/page.jsp?id=1024-bit-migration-faq#phasedout
Merge pull request #1 from petiepooo/patch-1

Change default keysize to 2048