0870cd1660 Remove Copy from PushBytesError (Tobin C. Harding)
Pull request description:
The `PushBytesError` is the only error type in the codebase to derive `Copy`. Without thinking too hard this is unusual - remove it.
Thinking a bit harder it makes the code less maintainable because we must commit to implementing `Copy`.
ACKs for top commit:
apoelstra:
ACK 0870cd1660edd21739cc94075e4b3a1c7f1a7d15; successfully ran local tests; lgtm
Tree-SHA512: c71db5de634dfe2bd76336e5c31fab496f2a472a8dd164034233544c15bd89c84ff986e476fa9b7b05d01aa5332dd4bc93f63a93bf7a21e9a0ec67fc145739b2