Revert use of protobuf's Gzip streams.

Unfortunately some Red Hat-based distributions lack the required header.
See https://bugzilla.redhat.com/show_bug.cgi?id=815587

This reverts commit 261a389a76.
This reverts commit b6736eb0a5.

src/network/compressor.h

@@ -0,0 +1,28 @@
+#ifndef COMPRESSOR_H
+#define COMPRESSOR_H
+
+#include <string>
+
+namespace Network {
+  class Compressor {
+  private:
+    static const int BUFFER_SIZE = 2048 * 2048; /* effective limit on terminal size */
+
+    unsigned char *buffer;
+
+  public:
+    Compressor() : buffer( NULL ) { buffer = new unsigned char[ BUFFER_SIZE ]; }
+    ~Compressor() { if ( buffer ) { delete[] buffer; } }
+
+    std::string compress_str( const std::string &input );
+    std::string uncompress_str( const std::string &input );
+
+    /* unused */
+    Compressor( const Compressor & );
+    Compressor & operator=( const Compressor & );
+  };
+
+  Compressor & get_compressor( void );
+}
+
+#endif