Various python3 related changes

- Use relative import for grgsm's modules
- Convert map to list
- Remove the hier_block.py workaround as as gnuradio 3.7 is no longer
  supported in this branch

Change-Id: I5ca8fd340823996e8c444aaf18ddacd85c92ab1c
diff --git a/python/__init__.py b/python/__init__.py
index 8241b01..557a8d6 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -42,24 +42,23 @@
 
 
 # import swig generated symbols into the gsm namespace
-from grgsm_swig import *
+from .grgsm_swig import *
 
 # import any pure python here
 
-from hier_block import hier_block
 #from fcch_burst_tagger import fcch_burst_tagger
 #from sch_detector import sch_detector
 #from fcch_detector import fcch_detector
-from clock_offset_corrector_tagged import clock_offset_corrector_tagged
-from gsm_input import gsm_input
-from gsm_bcch_ccch_demapper import gsm_bcch_ccch_demapper
-from gsm_bcch_ccch_sdcch4_demapper import gsm_bcch_ccch_sdcch4_demapper
-from gsm_sdcch8_demapper import gsm_sdcch8_demapper
-from gsm_gmsk_mod import gsm_gmsk_mod
-from fn_time import *
-from txtime_bursts_tagger import *
-import arfcn
-import device
+from .clock_offset_corrector_tagged import clock_offset_corrector_tagged
+from .gsm_input import gsm_input
+from .gsm_bcch_ccch_demapper import gsm_bcch_ccch_demapper
+from .gsm_bcch_ccch_sdcch4_demapper import gsm_bcch_ccch_sdcch4_demapper
+from .gsm_sdcch8_demapper import gsm_sdcch8_demapper
+from .gsm_gmsk_mod import gsm_gmsk_mod
+from .fn_time import *
+from .txtime_bursts_tagger import *
+from .arfcn import *
+from .device import *
 
 
 #