If no SSL certificates are provided, many Redis clients default to
disabling SSL peer verification. Previously it was a bit cumbersome to
configure this because the client would either have to reimplement
`redisCreateSSLContext()` or reach into the internals to set the
OpenSSL verify mode.
We can improve the SSL API by introducing a
`redisCreateSSLContextWithOptions()` call that takes into structured
parameters for SSL initialization. This structure contains a verify
mode that is used to set the OpenSSL verify mode.
Relates to https://github.com/redis/hiredis/issues/646
Housekeeping
* Check for C++ (#758, #750)
* Include `alloc.h` in `make install` and `cmake`
* Add a `.def` file for Windows (#760)
* Include allocation wrappers referenced in adapter headers
* Fix minor syntax errors and typos in README
* Fix CI in Windows by properly escaping arguments (#761)
