DSA opaque OpenSSL
dsa docs
move where we gc dsa data, improve dsa key checking
add generate_private_key to DSAParameters + add a new function to dsa

dsa.generate_private_key(key_size, backend) will allow you to generate a
new DSA key and implicitly generate new parameters. This streamlines the
common case and will be an avenue to support future backends that don't
allow independent generation of DSAParameters (e.g. CommonCrypto)
add note about enchant dependency for spellcheck in docs
Merge pull request #1188 from reaperhulk/fix-1167

add note about enchant dependency for spellcheck in docs
rename backend method, add some docs
Merge pull request #1179 from reaperhulk/dsa-numbers-opaque-backend

DSA Opaque Keys for OpenSSL
add multibackend support for new DSABackend method
Merge pull request #1189 from reaperhulk/dsa-new-method-multibackend

add multibackend support for new DSABackend method
deprecate concrete DSA classes and update DSA docs
deprecate DSA backend methods
split OpenSSL RSA enc/dec methods from backend
reorganize OpenSSL EC backend to remove some unneeded indirection
Merge pull request #1190 from reaperhulk/dsa-deprecate-concrete

deprecate concrete DSA classes and update DSA docs
Merge pull request #1191 from reaperhulk/dsa-deprecate-backend-methods

deprecate DSA backend methods
Merge pull request #1192 from reaperhulk/move-rsa-encryption-openssl

split OpenSSL RSA enc/dec methods from backend
Merge pull request #1193 from reaperhulk/simplify-some-ec-things

reorganize OpenSSL EC backend to remove some unneeded indirection
These functions can do their own GC now
Merge pull request #1194 from public/move-gc

These functions can do their own GC now