Feature/send large message (#14)

* introduce send fragment

* can pass a fin frame

* can send messages which are a perfect multiple of the chunk size

* set fin only for last fragment

* cleanup

* last fragment should be of type CONTINUATION

* Add simple send and receive programs

* speedups receiving + better way to wait for thing

* receive speedup by using linked list of chunks instead of large array

* document bug

* use chunks to receive data

* trailing spaces

examples/cobra_publisher/ixcrypto/IXBase64.h

@@ -11,4 +11,5 @@
 namespace ix
 {
     std::string base64_encode(const std::string& data, size_t len);
+    std::string base64_decode(const std::string& encoded_string);
 }