Merge pull request #27 from dermoth/master

Add instructions on using compressed InnoDB tables
New command Abe.admin.
Merge branch 'master' of github.com:jtobey/bitcoin-abe
Null out prev_block_id to avoid constraint error deleting block.
delete-chain-blocks: null out search_block_id.
delete-tx: new command.
link-txin: new command.
Merge bitcointools upstream changes and update callers.
* delete-chain-transactions: new command.
* rewind-datadir: new command.
Add --no-load config option

no-load skips loading blocks into the database, which is useful for a
"read-only" instance meant for serving from a shared database.

This is useful when having a dedicated instance loading blocks using
the --no-serve option so that "webserver" instances never block.