Version 2: IPFS integration

[prettydiff]

IPFS is - https://github.com/ipfs

IPFS is like bittorrent for filesystem fragments with git and hashing builtin. This means the publication task can safely eliminate the need to write and store zip files.

Major changes to biddle

• publish - Publication will work the same up till the point of writing a zip file. Instead a ipfs add -r child command will be issued against the temporary directory created for the variant. The filedata.json file will store the IPFS hash value instead of the local path to a zip file.
• install - Install will issue a ipfs get child command. Since IPFS has version control built in applications can be installed and updated without file clobbering, which solves a major biddle limitation.
• IPFS will become a required dependency just like Node. Biddle will not limit itself to a single form of IPFS so long as the generic commands are available from the system path.
• This major change should not require any changes to biddle's installed.json and published.json files.

Centralized management

• The publication task will still write files to a publication point, namely the latest.txt, index.xhtml, and filedata.json. This will provide a uniform location by which application metadata is stored without centralizing the actual application.