This PR adds support for sending contents of directories through the application.
Zip stream is used to send the directory structure.
The stored compression (so de facto no compression at all) is used except for files that are in zip format themselves. In such case the files are compressed with bzip2.
There is no check of the hash in case of directories. Zip library internally checks CRC32 checksums instead.
This PR adds support for sending contents of directories through the application.