Fixed all hierarchical blocks in the project
by adding a hier_block class that solves incompatibility between GNU Radio >=3.7.9 and <=3.7.8
and inheriting all hierarchical blocks from it.
This commit fixes #135
diff --git a/python/receiver/gsm_input.py b/python/receiver/gsm_input.py
index 191f950..2de2f03 100644
--- a/python/receiver/gsm_input.py
+++ b/python/receiver/gsm_input.py
@@ -13,10 +13,10 @@
 from distutils.version import LooseVersion as version
 import grgsm
 
-class gsm_input(gr.hier_block2):
+class gsm_input(grgsm.hier_block):
 
     def __init__(self, ppm=0, osr=4, fc=940e6, samp_rate_in=1e6):
-        gr.hier_block2.__init__(
+        grgsm.hier_block.__init__(
             self, "GSM input adaptor",
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),