CI: switch to Miniconda3 when testing on travis

conda sources seem more buggy on Python 2.7.
[see conda/conda-build issue 3309]

Author: pavoljuhas

.travis.yml

@@ -45,9 +45,9 @@ before_install:
   - MYMCREPO=https://repo.continuum.io/miniconda
   - case ${TRAVIS_OS_NAME} in
     linux)
-        MYMCBUNDLE=Miniconda2-latest-Linux-x86_64.sh ;;
+        MYMCBUNDLE=Miniconda3-latest-Linux-x86_64.sh ;;
     osx)
-        MYMCBUNDLE=Miniconda2-latest-MacOSX-x86_64.sh ;;
+        MYMCBUNDLE=Miniconda3-latest-MacOSX-x86_64.sh ;;
     *)
         echo "Unsupported operating system." >&2;
         exit 2 ;;