Add support for indicating an upstream package server.
Use setuptools.
Download package from PyPi if not present locally
default version is empty string
Merged in dotsbb/pypicache/dotsbb/download-package-from-pypi-if-not-presen-1382524136297 (pull request #3)

Download package from PyPi if not present locally
New feature could overwrite if packages are snapshots or dev versions
Fixed mistake with filename variable
package list for /simple
package list added to /simple
Merged in schinckel/pypicache (pull request #1)

Add support for indicating an upstream package server.
Adding a note on devpi as an alternative.
Merged in otioti/pypicache (pull request #5)

Could overwrite file packages if versions are SNAPSHOT or DEV
Merged in szinsli/pypicache (pull request #6)

Package list for /simple