add cryptonight_v8_double

[psychocrypt]

close: #2263

Add new algorithm alias for cryptonight_v8_double. The difference to v8
is that the number of iterations is increased.

Add also the currency X-CASH which use cryptonight_double.

[AnimusXCASH]

Hi,
mining pool
http://minexcash.com/#getting_started

The difference from our algo to regular CN V8 is we have double the iterations than CN V8. the scratchpad is still 2MB

Where do you want that I send you wallet?

[psychocrypt]

Thx I already found the online wallet generator. I needed only a address for the short tests against a pool. Since the pow only changed the number of iterations it was easy to integrate it.

[AnimusXCASH]

Thx I already found the online wallet generator. I needed only a address
for the short tests against a pool. Since the pow only changed the number
of iterations it was easy to integrate it.

great, could you give as an EST. time when it will be integrated?

thanks

[psychocrypt]

my personal schedule is to release in the next 24h.