Moved _SQLwrite call outside Quandl_sourcelist class

Added operation switches to _SQLwrite
-- debug(false): enables debug printing
-- hard_overwrite(true): enables "ON DUPLICATE KEY UPDATE" functionality

Added None->NULL conversion to _SQLwrite

Removed hanging fetchResults method from _sourcelist class

Updated init.ini to match "quanDl" not "quanTl"

Updated quandl_sources.sql to match new naming scheme (spelling error)
fixed quandl_sources.sql source_freshness index