bugfix: config files for worker and balancer not being loaded correctly.
deleted obselete build file.
publisher can be enabled and disabled dynamically.
improve format of blk published data.
expanded explanation.
added page describing publisher to doc.
accidentally nested section in another sibling.
added about fetch_block_transaction_hashes to doc.
consistent formatting (doc)
alwas show config file being used.
added blockchain.fetch_block_transaction_hashes to worker.
for consistency with fetch history we don't include the list size.
add from_height to *fetch_history() outputs.
Added fetch_block_transaction_hashes attach to worker main.cpp

prefixed with blockchain_ in blockchain.cpp to match naming style of other methods.