Merge pull request #6 from steved555/master

add :symbolize_keys option to JSON parsing
v0.1.8
JWK.parse to generate RSA public key from JWK json
remove 1.9.2 support for now
v0.2.0
notes for 1.9.3 requirement
pem difference between 1.9.2 and 1.9.3 seems OK for JWK usage
allow skipping verification when decoding
remove 1.8.x support
allow string value for jwk alg
0.3.0 is not released yet
v0.3.0
coverage 100%
rename JWK's exp to xpo because of spec change
v0.3.1
legacy jwk format support (for connect interop)
v0.3.2
more legacy jwk format support
Revert "v0.3.2"

This reverts commit 8dd1d16d61734223e9292819f693757c8d2d0256.
v0.3.2