release 4.15

Signed-off-by: Arik Sosman <[email protected]>

up package version to 4.13.0

Signed-off-by: Arik Sosman <[email protected]>

Change package.json

Reviewers: arik

Reviewed By: arik

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D6994

Update vulnerable dependencies based on TRM feedback

Summary:
I've updated the following dependencies: express, body-parser, morgan, npm, mocha, and coveralls.

Mocha and coveralls were major version updates - the main breaking change in both is that they remove support for Node versions <4. That shouldn't affect us, and I verified that the other small breaking changes in Mocha did not affect our test suite,

To test that the SDK  still works, I ran some of the scripts in the `example/` directory, as well as run our test suite. It had the same amount of failing tests as before, and all of the core wallet tests (create wallet sign transaction, sned transaction, new address, etc), pass.

Reviewers: arik, alex

Reviewed By: alex

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D6906

improve inheritance mechanism such that accidental overwrites are no …

…longer possible

Summary: Signed-off-by: Arik Sosman <[email protected]>

Reviewers: kevin, zacleids, benchan, alex

Reviewed By: alex

Subscribers: otto, alex, ben

Differential Revision: https://phabricator.bitgo.com/D6823

expose BCH through the module

Summary: Signed-off-by: Arik Sosman <[email protected]>

Reviewers: ben, kevin

Reviewed By: kevin

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D6799

update SDK to 4.8

Signed-off-by: Arik Sosman <[email protected]>

version bump to v4.9.0

replace the default network

Summary: Signed-off-by: Arik Sosman <[email protected]>

Reviewers: robert

Reviewed By: robert

Subscribers: ben

Differential Revision: https://phabricator.bitgo.com/D6773