Issue 72 - support DS160 as alg name
leverage the environment for commands in package.json
back out previous format work, to be re-introduced.
initial support for new key formats, unpadded base64url encoded, triggered by presence of .kty
parsing of new format DSA keys
package.json version bump to indicate the sweeping changes occuring on this branch
remove accidental addition
partial
always generate new format keys
always generate base64*url* unpadded for key serialization
represent times in all formats in seconds
remove support for node 0.6
extract 'sub' from certificates
Force new certificates to use the new alg names

Stricter rules for certificates formats:

- old format certs required to use an alias
- new format certs forbidden from using an alias

This breaks the old API for generating certificates and requires
users to update the certificate algorithm in their code.
Upgrade 'principal.email' to 'sub' during verification

The old format certs should continue to load properly but their
'principal.email' value now needs to be called 'sub'.
Require the new cert format when signing

Ignore the principal attribute in certificates when signing
certificates since we should require new format certs.

This breaks existing BrowserID shims that haven't upgraded to the
new certificate format yet.
update generate-keypair script to specify full keytype (DSA and not DS)
update certify program to conform to new data formats
s/public-key/pubkey/
revert changes to sub - they prevent backwards compatibility with sub-properties under principal