Merge pull request #4 from pigeonflight/master

Unified installer build; pulls eggs and download cache from unified installer
Rename REMOTE_PLONE -> EXTENDS
Rename

PLONE_UNIFIEDINSTALLER => UNIFIEDINSTALLER_URL
PACKAGE_NAME => UNIFIEDINSTALLER_DIR
Flake8 fixes
Merge remote-tracking branch 'upstream/master'
some flake8 clean up
removed the reference to easy_install in README, now base testing on make pre