Support compressed public keys in PrivateKey.js
save private keys in base58 format

...to allow them to be imported into other wallets, preserving the "compressed"
or "uncompressed" state of the public key in the private key representation.
fix validate math error
Merge pull request #9 from ryanxcharles/feature/compressed-public-keys

Save private keys in base58check encoded format
Export transaction constants for use in cosign
Merge pull request #11 from ryanxcharles/feature/export-transaction-constants

Export transaction constants for use in cosign
negative indexes don't work in javascript
must use new operator to make new Put
Merge pull request #12 from maraoz/task/readme

Installation guide for Ubuntu added to README file and some ignores
Merge pull request #13 from ryanxcharles/bug/multisig-bugs

fix bugs for cosign
various small changes to bitcore
Merge pull request #14 from maraoz/misc

various small changes to bitcore