ported nix/build-all.sh to python in order to be able to provide any feedback

for the user at all (shell scripts systematically are working against providing
any useful user feedback, so the port is the only option)

.travis.yml

@@ -33,6 +33,11 @@ install:
   - sudo apt-get install -y libpcre3-dev
 
 script:
+# test nix/build-all.py script (before the build following build instructions in order to no mess up installations into /usr/local)
+  - cd nix
+  - python build-all.py
+  - cd ..
+# test build according to build instructions
   - pwd
   - cd ..
   - git clone https://github.com/KhronosGroup/OpenCOLLADA.git
@@ -53,3 +58,9 @@ script:
   - cd build
   - cmake -DCOLLADA_SUPPORT=True -DOPENCOLLADA_INCLUDE_DIR=/usr/local/include/opencollada -DOPENCOLLADA_LIBRARY_DIR=/usr/local/lib/opencollada -DPCRE_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu -DUSE_IFC4=False -DBUILD_IFCPYTHON=True -DUNICODE_SUPPORT=True -DOCC_LIBRARY_DIR=/usr/lib/x86_64-linux-gnu  ..
   - make -j2
+  - pwd
+  - cd ..
+  - cd ..
+
+after_failure:
+  - cat build/Linux/x86_64/logs/*.log