Listminting RPC

Here is the listminting RPC command. 
I only defined 2 arguments yet (count and from) to control the output.

I had an issue to handle arguments cast that i managed to work around here : 
https://github.com/daeMOn63/Peerunity/blob/listminting_rpc/src/bitcoinrpc.cpp#L972

but i expected to get it working like defined here : 
https://github.com/daeMOn63/Peerunity/blob/listminting_rpc/src/bitcoinrpc.cpp#L1051
But if i use this method, i get a `error: {"code":-1,"message":"value is type str, expected int"}`

 any thoughts ?