Some cleanups to imports
pep8, irony
Merge pull request #890 from alex/import-cleanup

Some cleanups to imports
BN_CTX bindings
BN_cmp macro
Merge pull request #891 from public/bn-ctx-binding

BN_CTX bindings
BN_cmp returns an int, not a BIGNUM *
Merge pull request #892 from reaperhulk/bn-fix

BN_cmp returns an int, not a BIGNUM *
Merge branch 'master' into compiler-warnings-error