Log KoreServer output

[tothtamas28]

Stream output from kore-rpc and kore-rpc-booster into a Logger, instead of the standard output / error stream of the parent.

[tothtamas28]

Example output:

INFO:pyk.kore.rpc:Starting KoreServer: kore-rpc-booster imp-kompiled/definition.kore --module IMP --server-port 0 --llvm-backend-library imp-llvm-kompiled/interpreter.so
INFO:pyk.kore.rpc:[PID=192489][stde] [proxy] Loading definition from imp-kompiled/definition.kore, main module "IMP"
INFO:pyk.kore.rpc:KoreServer started: 0.0.0.0:45707, pid=192489
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Reading the input file TimeSpec {sec = 0, nsec = 1685789}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Parsing the file TimeSpec {sec = 0, nsec = 130}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Verifying the definition TimeSpec {sec = 0, nsec = 150}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Executing TimeSpec {sec = 0, nsec = 129753021}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Reading the input file TimeSpec {sec = 0, nsec = 2713788}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Parsing the file TimeSpec {sec = 0, nsec = 140}
INFO:pyk.kore.rpc:[PID=192489][stde] [kore][info] Verifying the definition TimeSpec {sec = 0, nsec = 130}
INFO:pyk.kore.rpc:[PID=192489][stde] [proxy] Starting RPC server

[geo2a]

LGTM