Build cefpython .so modules using clean Python installations as in pyenv to avoid invalid symbols being embedded in the .so module #266

Built cefpython_py27.so module using system Python 2.7.6 on Ubuntu 14.04. Then installed the package with pyenv Python 2.7.12 and tried to run the example and got error:

ImportError: /home/cz/.pyenv/versions/2.7.12/lib/python2.7
/site-packages/cefpython3/cefpython_py27.so: undefined symbol: PyFPE_jbuf

The resulting cefpython_py27.so when building using system Python is about 8.9 MB in size. When building using pyenv Python installations they are about half in size betwen 4.3 ~ 4.6 MB. Looks like there are some redundant symbols being embedded when using system Python. And this causes errors when running with a different Python installation, like the above error message about undefined symbol.