Add preliminary documentation for Beaverfiles
Switch block manifests to YAML

Modify the documentation so that block manifests use YAML instead of
INI format.  This is more suitable for us because it allows us to a lot
of nesting with lists and dictionaries, necessary for specifying
multiple modes with a various parameters.  We could do this with INI
sections, but it’s messy, and we can’t nest them.  We’ll be adding more
stuff to these files later, and YAML just keeps it cleaner.
Add Beaverfile parser to 'create' command

Parses Beaverfile as per Beaverfile spec in docs/beaverfiles.md
Rename 'create' to 'stack'; add 'blockify'

Create functions for instantiating blocks. Rename ‘create’ to ‘stack’
for less ambiguity.
Add Blockfile parser

Sanitizes against directory traversal to enforce modularity in
Blockfile configuration files.
Complete 'blockify' command

Add code to build Docker containers based on Dockerfiles specified in
Blockfile.
Add basic database schema

Add schema for barebones SQLite database located at
/var/lib/beaver/data.sql for persistent storage. Contains simple Image,
Container, Block, Stack, and RunningBlock classes for now, and contains
code to set up the SQLite database if it doesn’t exist
Fix 'blockify' Dockerfile directory parsing
Add CLI log stub, validation functions
Fix error statements, add DB code to 'stack'
Add relationships to db classes
Increase Container ID length to 64 characters

The full ID is necessary in some cases
Add logging aggregation capability
Bugfix: stack name validator: validate by name instead of ID

validate_running_stack_name was validating ID’s instead of names. Oops.
Finish implementing 'stack' function

Requires ‘blockify’ functionality, but ‘blockify’ cannot be run
properly with decorators from click; therefore, its code content moved
to ‘blockfile_to_block’.
Fix Docker build command in block generation
Fix database schema Image relationship
Fix database models for proper id lengths
Add database transaction code to blockfile handler

Updates the sqlite database with newly created blocks.
Rename some variable names in db.py for clarity