Merge pull request #1092 from karlnapf/develop

some NULL checks for equals method
CSGObject::equals method

-hardcoded ignore of 'num_elements'
-use ``only'' double in precision (floatmax_t is not supported by swig)
-fixed floatmax_t issues from Sören's commit
-moved num_lements check of DynamicObjectArray to CSGObject (cleaner)
-added some new unit tests for num_elements and some NULL cases