Combine with netscape.security

[cipherboy]

While we likely won't be able to fully collapse org.mozilla.jss.netscape.security into the rest of the org.mozilla.jss classes, it'd be nice to combine these a little better. Some obvious examples that I've seen are:

• Combine ASN.1 parsing into a single set of classes,
• Combine X.509 Certificate handling into a single set of classes,
• Combine the org.mozilla.jss.netscape.security.provider into the base JSS provider,
• Combine some of the utilities into base JSS,

It'd be great if we could do this in such a way that the old usages of org.mozilla.jss continue to function, and anyone using the org.mozilla.jss.netscape.security classes can simply swap in the new ones.

Help is definitely wanted!

This issue probably depends on #244.