* imc_channel, imc_raw: optimize with pass by reference

* imc_object: asc_time, localtime: make threadsafe
* imc_datatype: satisfy 'rule of two'
* python: remove all unused imports

python/example.py

@@ -5,7 +5,6 @@ import raw_eater
 import raw_meat
 import pyarrow as pa
 import pyarrow.parquet as pq
-import glob
 from pathlib import Path
 
 fileobj1 = Path("smp/Rangerover_Evoque_F-RR534_2019-05-07/").rglob("*.raw")

python/usage_adv.py

@@ -1,9 +1,7 @@
 
 import imc_termite
 import json
-import glob
 import os
-from pathlib import Path
 
 # list files in sample directory
 # fileobj1 = Path("samples/").rglob("*.raw")