ensure uncompressed addresses are on same bitcoin network

support uncompressed to_address

* master:
  support uncompressed addresses
  ensure subnodes are on same bitcoin network
  Group is already removed by EC_KEY_free
  clear and free EC_GROUP object
  Adding unit tests for OpenSSL extensions
  Clearing and freeing pointers
  Fixing memory leak, need to free EC_POINT objects
  Validating inputs: must be points or it can segfault
  Updating test suite to use :expect notation instead of :should (https://github.com/rspec/rspec-expectations/blob/master/Should.md)

* develop:
  nil'd after freeing

Money-Tree, in essence is a key-derivation tool.
The keys it derives are not aware of the 'coin',
or 'version'. So there is now no notion of network
held as state on anything.

Money-Tree derives keys, and in the various forms of serialization
you can specify which type of coin (version bytes) you'd like to use.

Although it may seem tedious, it allows trees to be
coin-agnostic until serialization (and theoretically
the usage of the same key-pairs for different coin
addresses.)

If the user provides a NETWORK that is not
recognized, we throw an error.

Rename to_serialized_address to to_bip32
same for from_serialized_address.

Deprecate old methods.

Remove network state

update deprecated calls in specs

make readme use to/from_bip32

**What changed?**
* Have all internal exceptions descend from `StandardError` rather than `Exception`.

**Why?**
* This is a Ruby gotcha (see link below). Essentially using `rescue => e` will not catch any of
  these exceptions as this only catches subclasses of `StandardError`. This can cause users of the
  library to get unexpected results when implementing error handling this way.

**References**
[Rescue StandardError, Not Exception](https://robots.thoughtbot.com/rescue-standarderror-not-exception)

Get rid of Bignum deprecation for ruby 2.4+

Support more libssl library names so this will work on heroku

Update key.rb to support ruby 2.4+ without deprecation warnings

adds extra libssl location

for integration with external security scanner services, i.e. https://snyk.io/