blockchain_export can now export to a blocks.dat format

Also make the number of blocks endian independant, and add
support for testnet

src/blockchain_utilities/CMakeLists.txt

@@ -38,11 +38,13 @@ bitmonero_private_headers(blockchain_converter
 set(blockchain_import_sources
   blockchain_import.cpp
   bootstrap_file.cpp
+  blocksdat_file.cpp
   )
 
 set(blockchain_import_private_headers
   fake_core.h
   bootstrap_file.h
+  blocksdat_file.h
   bootstrap_serialization.h
   )
 
@@ -52,10 +54,12 @@ bitmonero_private_headers(blockchain_import
 set(blockchain_export_sources
   blockchain_export.cpp
   bootstrap_file.cpp
+  blocksdat_file.cpp
   )
 
 set(blockchain_export_private_headers
   bootstrap_file.h
+  blocksdat_file.h
   bootstrap_serialization.h
   )