Add pseudo `ensurepip`
Enable pseudo _ensurepip_ for existing definitions
Rename functions

  * `build_package_setuptools` -> `build_package_ez_setup`
  * `build_package_pip` -> `build_package_getpip`
Pass ez_setup.py and get-pip.py via argument instead of STDIN

AFAIK, Jython 2.7b2 could not handle ez_setup.py via STDIN
s/getpip/get_pip/g
Merge pull request #194 from yyuu/pseudo-ensurepip

Use `ez_setup.py` and `get-pip.py` to setup pip