Refactor BER decoder into a suspendable coroutine

The goal of this change is to make the decoder stopping on input
data starvation and resuming from where it stopped whenever the
caller decides to try again (hopefully making sure that some more
input becomes available).

This change makes it possible for the decoder to operate on streams
of data (meaning that the entire DER blob might not be immediately
available on input).

On top of that, the decoder yields partially reconstructed ASN.1
object on input starvation making it possible for the caller to
inspect what has been decoded so far and possibly consume partial
ASN.1 data.

All these new feature are natively available through
`StreamingDecoder` class. Previously published API is implemented
as a thin wrapper on top of that ensuring backward compatibility.

CHANGES.rst

@@ -1,8 +1,26 @@
 
-Revision 0.4.8, released XX-09-2019
+Revision 0.5.0, released XX-09-2019
 -----------------------------------
 
-No changes yet.
+- Refactor BER/CER/DER decoder into a coroutine.
+
+  The goal of this change is to make the decoder stopping on input
+  data starvation and resuming from where it stopped whenever the
+  caller decides to try again (hopefully making sure that some more
+  input becomes available).
+
+  This change makes it possible for the decoder to operate on streams
+  of data (meaning that the entire DER blob might not be immediately
+  available on input).
+
+  On top of that, the decoder yields partially reconstructed ASN.1
+  object on input starvation making it possible for the caller to
+  inspect what has been decoded so far and possibly consume partial
+  ASN.1 data.
+
+  All these new feature are natively available through
+  `StreamingDecoder` class. Previously published API is implemented
+  as a thin wrapper on top of that ensuring backward compatibility.
 
 Revision 0.4.7, released 01-09-2019
 -----------------------------------

README.md

@@ -18,6 +18,7 @@ Features
 
 * Generic implementation of ASN.1 types (X.208)
 * Standards compliant BER/CER/DER codecs
+* Can operate on streams of serialized data
 * Dumps/loads ASN.1 structures from Python types
 * 100% Python, works with Python 2.4 up to Python 3.7
 * MT-safe