show scriptSig signature hash types in transaction decodes. fixes #3166

show scriptSig signature hash types. fixes #3166

Please give this a look and let me know if you'd like it changed or if I mis-understood the issue request.

The fix basically appends the scriptSig signature hash types, within parentheses, onto the end of the signature(s) in the various "asm" json outputs. That's just the first formatting idea that came to my mind.

Added some tests for this too.
Indexing a std::map with [x] adds an entry with the default value for the type (in this case, an empty string), if the key doesn't exist in the map. This is not thread-safe, and makes it possible to consume some memory by providing unknown `sigHashTypes`.

- please make `mapSigHashTypes` const
- use `.find(x)` instead of `[x]` to find the value