Add development deps to Gemfile for easy bootstraping
move eventmachine, rake and bacon to Gemfile
Run bacon so rake exits 1 when failing
to_pubkey_script_sig supports compressed pubkeys
ignore log4r warning in require_dependency
Bitcoin::Script: invalid if script larger than 10_000 bytes
add Bitcoin::Script::DISABLED_OPCODES
add Bitcoin#network_project
fix warnings

  lib/bitcoin/script.rb:94: warning: already initialized constant OP_2MUL
  lib/bitcoin/script.rb:95: warning: already initialized constant OP_2DIV
  spec/bitcoin/spec_helper.rb:75: warning: already initialized constant CHECKPOINTS
add generate_tx.rb and simple_network_monitor_and_util.rb examples
add basic ppcoin support
add basic litecoin support
add basic freicoin support
store cumulative block work as bigint
validation: pass block timestamp to signature verification and ignore difficulty on testnet3
create keystore file if it doesn't exist
basic support for namecoin network

can sync the chain and answer name_show requests

TODO:
- merged-mining validations
- namecoin validations
- namecoin address version
- create namecoin tx
receive/send NMC, create and spend name_* tx, better indexing, namecoin testnet
storage: don't cache head block by default

only instances that add new blocks should enable this,
otherwise your head won't get updated if blocks are added by someone else.
fix #get_name_hash