pyenv 0.4.0-20140311

Changes:

* python-build: Add new CPython releases; 3.3.5
* python-build: Add new CPython release candidates; 3.4.0rc1, 3.4.0rc2, 3.4.0rc3
* python-build: Update default setuptools version (2.2 -> 3.1)
* python-build: Update default pip version (1.5.2 -> 1.5.4)
* python-build: Import recent changes from ruby-build v20140225