BIP39 implementation
Separate out BIP39
BIP39 in browser
Switch BIP-0039 to sjcl in browser
remove unbuilding c code, and ...

* Remove c code that didn't compile on my machine
* Replace with sjcl code
* Minor modifications to mnemonic interface more bitcoreish
add concept of "main" bundle and remove BIP39

Some features of bitcore will be too large to be included in the browser bundle
by default. Since BIP39 pretty much requires the giant list of words to be
used, I am excluding it by default. The ability to exclude some features by
default will become useful with some particularly large features to come,
particularly BIP70.
Merge remote-tracking branch 'devrandom/bip39'

Conflicts:
	test/index.html
Merge branch 'bip39'

Conflicts:
	browser/bundle.js
add explanation of building the browser bundle to README