add new SecureRandom class that does the right thing

Generating random numbers properly depends on the platform. The new
getRandomBuffer method does the right thing on the right platform. It will
sometimes fail due to insufficient entropy. The getPseudoRandomBuffer class is
also provided that will never fail, but it is not cryptographically secure and
should not be used for keys.
fix issues with ConnectionTor example and Connection class
remove unnecessary "change" console.log from Electrum test
use SecureRandom in Key in the browser

...to make sure random numbers are generated securely
rng statistic testswq
testing RNG
fix runs test
reduce number of cases for browser
skip pending tests:wq
skip statistically failing tests
Merge pull request #284 from maraoz/test/rng

Tests for RNG
Key should make sure new privkey is less than N

...this involves adding a Curve class, and significant refactoring to make this
possible in a clean way.
removes buffertools dependencies in browsers Key.js
Merge pull request #285 from matiu/bug/firefox1

removes buffertools dependencies in browsers Key.js
Merge branch 'feature/secure-random'

Conflicts:
	lib/browser/Key.js
up version to 0.1.13

New things:
* Statistical tests for RNG
* New SecureRandom class that does the right thing on all platforms
* Peer discovery
* Signature sorting in TransactionBuilder
* BIP32 speed improvements
* Electrum-style public key derivation
* Refactor node/browser code
* Message signing/verification the bitcoin way
* Address.fromScriptPubKey
add require('bignum') in key
Merge pull request #288 from ryanxcharles/bug/bignum-in-key

add require('bignum') in key
version 0.1.14
added Script.getMultiSigInfo as easy helper to return information about a multisig script