CMake: update path to install python binding

Install python libs with python interface.
Fix #20

.travis.yml

@@ -25,5 +25,5 @@ script:
 
   # tests
   - cd ${TRAVIS_BUILD_DIR}
-  - export PYTHONPATH=$PYTHONPATH:`pwd`/install/lib/python/site-packages
+  - export PYTHONPATH=$PYTHONPATH:`pwd`/install/lib/python2.7/site-packages
   - nosetests pyTest

src/CMakeLists.txt

@@ -72,16 +72,23 @@ if(SWIG_FOUND)
 		endif()
 		swig_link_libraries(sequenceparser-py sequenceparser-shared ${PYTHON_LIBRARIES})
 
+		# Get path to install python binding
+		if(PYTHONLIBS_VERSION_STRING)  # CMake >=2.8.11
+			string(SUBSTRING ${PYTHONLIBS_VERSION_STRING} 0 3 PYTHON_VERSION)
+		else()
+			set(PYTHON_VERSION ${SEQUENCEPARSER_PYTHON_VERSION})
+		endif()
+		set(SEQUENCEPARSER_PYTHON_MODULE_OUTPUT_DIR "lib/python${PYTHON_VERSION}/site-packages/pySequenceParser/")
+
 		# Install python interface
 		set(SEQUENCEPARSER_PYTHON_BINDING_FILE "${CMAKE_SWIG_OUTDIR}/sequenceParser.py")
-		set(SEQUENCEPARSER_PYTHON_MODULE_OUTPUT_DIR "lib/python${PYTHONLIBS_VERSION_STRING}/site-packages/pySequenceParser/")
 		install(
 			FILES ${SEQUENCEPARSER_PYTHON_BINDING_FILE} ${SEQUENCEPARSER_PYTHON_INIT_FILE}
 			DESTINATION ${SEQUENCEPARSER_PYTHON_MODULE_OUTPUT_DIR}
 			OPTIONAL
 		)
 		# Install python lib and __init__.py files
-		install(TARGETS ${SWIG_MODULE_sequenceparser-py_REAL_NAME} DESTINATION "lib/python${PYTHONLIBS_VERSION_STRING}/site-packages/pySequenceParser/" OPTIONAL)
+		install(TARGETS ${SWIG_MODULE_sequenceparser-py_REAL_NAME} DESTINATION "${SEQUENCEPARSER_PYTHON_MODULE_OUTPUT_DIR}" OPTIONAL)
 		install(CODE "file(WRITE ${CMAKE_INSTALL_PREFIX}/${SEQUENCEPARSER_PYTHON_MODULE_OUTPUT_DIR}/__init__.py)")
 	else()
 		message("PYTHON not found, will not build python binding.")