fix travis build problem by transferring pre-installing to rnd_requirements.txt

.travis.yml

@@ -26,8 +26,6 @@ matrix:
             - python-nose
             - python-mock
 before_install:
-  - pip install https://github.com/pyexcel/pyexcel-io/archive/master.zip
-  - pip install https://github.com/pyexcel/pyexcel/archive/master.zip
   - if [[ $TRAVIS_PYTHON_VERSION == "2.6" ]]; then pip install ordereddict; fi
   - if [[ -f min_requirements.txt && "$MINREQ" -eq 1 ]]; then
       mv min_requirements.txt requirements.txt ;