Refactor faucet funds creation

[daria305]

Fixes #43
Problem was not connected to the wallet handling mechanic, but the funds preparation might went bad and no more funds were prepared until timeout was over. Now multiple routines can prepare funds at once, and spammer does not stop on errors with funds preparation.

• Funds are now created in the background, and spammer starts if it has outputs ready for at least 3minute spam.
• tool will no longer stop when there is an error while funds are prepared, it will keep trying to request and split funds
• user can now add additional issuer keys for the faucet request, to avoid problems with funds preparation for heavy spams
• no restrictions for the duration param, can by as large as user wants to
• size of the wallet is added to tools parameters, so the user can easily reduce the split number for funds preparation (each faucet output is split into x outputs, and split again, so for splitNumber x we have x*x wallet size and x+1 additional transactions are issued to split the funds.