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/cmake/Modules/GrccCompile.cmake b/cmake/Modules/GrccCompile.cmake
index 4589fd4..d2bc2d8 100644
--- a/cmake/Modules/GrccCompile.cmake
+++ b/cmake/Modules/GrccCompile.cmake
@@ -39,6 +39,7 @@
         OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${file_name}
         COMMAND "${CMAKE_COMMAND}"
         -E env PYTHONPATH="${PYTHONPATH}" GRC_BLOCKS_PATH=${CMAKE_SOURCE_DIR}/grc
+        CMAKE_BINARY_DIR=${CMAKE_BINARY_DIR}
         ${GRCC} -o ${CMAKE_CURRENT_BINARY_DIR}
         ${CMAKE_CURRENT_SOURCE_DIR}/${file_name}.grc
         COMMAND "${CMAKE_COMMAND}" -E rename ${CMAKE_CURRENT_BINARY_DIR}/${file_name}.py ${CMAKE_CURRENT_BINARY_DIR}/${file_name}