Add a JSON-RPC client library

[mycognosist]

Now that EBT is working reliably, I'm focusing on making it easier to interact with solar in an application context. I think the addition of a JSON-RPC client library will be a significant step forward.

API

• [x] blocks
• [x] blockers
• [x] descriptions
• [x] self_descriptions
• [x] latest_description
• [x] latest_self_description
• [x] feed
• [x] follows
• [x] followers
• [x] is_following
• [x] friends
• [x] images
• [x] self_images
• [x] latest_image
• [x] latest_self_image
• [x] message
• [x] names
• [x] self_names
• [x] latest_name
• [x] latest_self_name
• [x] peers
• [x] ping
• [x] publish
• [x] subscribers
• [x] subscriptions
• [x] whoami

[mycognosist]

CC: @black-puppydog

Interacting with solar programmatically is now a little easier (JSON-RPC client).