README: update download link to 0.3.8
ASN1: fix issue with non-constructed context-specific tags
ASN1: add unit test for non-constructed context-specific change
ASN1: fix unit test
Merge pull request #480 from terrafrost/asn1-fix

ASN1: fix issue with non-constructed context-specific tags

* terrafrost/asn1-fix:
  ASN1: fix unit test
  ASN1: add unit test for non-constructed context-specific change
  ASN1: fix issue with non-constructed context-specific tags