pyenv 0.4.0-20140211

Changes:

* pyenv: Always append the directory at the top of the `$PATH` to return proper value for `sys.executable`
* pyenv: Unset `GREP_OPTIONS` to avoid issues of conflicting options
* python-build: Install `pip` with using `ensurepip` if available
* python-build: Add support for framework installation (`--enable-framework`) of CPython
* python-build: Import `bats` tests from ruby-build v20140110.1
* python-build: Add new CPython release candidates; 3.3.4, 3.4.0b3
* python-build: Add [Anaconda](https://store.continuum.io/cshop/anaconda/) and [Miniconda](http://repo.continuum.io/miniconda/) binary distributions
* python-build: Display error if the wget does not support Server Name Indication (SNI) to avoid SSL verification error when downloading from https://pypi.python.org.
* python-build: Update default setuptools version (2.1 -> 2.2)
* python-build: Update default pip version (1.5.1 -> 1.5.2)
* python-build: Import recent changes from ruby-build v20140204