Merge bitcoindevkit/bdk#585: set coin type based on network

db9d43ed2f4146dbfdc28a72d0c9ae420f831fc3 use network to set coin type (Esraa Jbara)

Pull request description:

  resolves #578

  * [x] This pull request breaks the existing API
  * [x] I've added tests to reproduce the issue which are now passing
  * [x] I'm linking the issue being fixed by this PR

ACKs for top commit:
  danielabrozzoni:
    re-ACK db9d43ed2f4146dbfdc28a72d0c9ae420f831fc3
  afilini:
    re-ACK db9d43ed2f4146dbfdc28a72d0c9ae420f831fc3

Tree-SHA512: 0310a09ef21c6fc792688a9ccc19221b1cffaeceefd34f4c83f206e965abe963a78f9e4ca53db046b39e7bf1be118a101afe5c08c43f06ecf35ed9536102cd9b