Fix grcc compilation with python3 by adding local subdirs to __path__

As the directory structure in the repository is different then the one
after the package gets installed we need to add those subdirectories to
the __path__ otherwise python3 is not able to load the modules using the
relative import syntax and grcc compilation and some unit tests fail.

Mofiy __path__ only when the CMAKE_BINARY_DIR environment variable is
present.

Revert "grgsm_livemon: Set cell_allocation to [0]"

This reverts commit 013d4c258c6ad31c2581f0caa4eee3aa609fd9de.

Change-Id: I223fd6181e8e36027039301186b671712a597ff8
diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
index f0c984d..9cd7045 100644
--- a/python/CMakeLists.txt
+++ b/python/CMakeLists.txt
@@ -47,7 +47,8 @@
 include(GrTest)
 
 set(GR_TEST_TARGET_DEPS gr-gsm)
-set(GR_TEST_PYTHON_DIRS ${CMAKE_BINARY_DIR}/swig:${CMAKE_BINARY_DIR}/python/misc_utils:${CMAKE_BINARY_DIR}/python/receiver:${CMAKE_BINARY_DIR}/python/demapping:${CMAKE_BINARY_DIR}/python/transmitter)
+set(GR_TEST_PYTHON_DIRS ${CMAKE_BINARY_DIR}/swig:${CMAKE_BINARY_DIR}/python/misc_utils)
+set(GR_TEST_ENVIRONS "CMAKE_BINARY_DIR=${CMAKE_BINARY_DIR}")
 GR_ADD_TEST(qa_arfcn ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/qa_arfcn.py)
 GR_ADD_TEST(qa_decryption ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/qa_decryption.py)
 GR_ADD_TEST(qa_burst_printer ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/qa_burst_printer.py)