Import file in binary field

Importing binary field is quiet difficult for now.
Here are the ways to achieve importing of binary fields:
- Use RPC with external program.
- Use Base64 encoded, XML, CSV, YAML

So for embedding binary data into module: only Base64 is available.

Having physical file could be easier:
- physical file "icon.png" in the module directory.
- In CSV, XML, YAML file, use "@icon.png" or something like this as field value.
Notice that the "@" is not in Base64 allowed characters.

So if the import parser finds data (for binary field) that begin with "@" it will search for the file, and getting its content.