removed sp caching

all requests for sp result in file load

this change aims to work better with external changes to
server.properties so that changes aren't ignored by the existence of
_sp.props
extract_server_name moved to mineos module

currently coexists in server branch; will be removed in merge.
Merge remote-tracking branch 'origin/master' into server
removed redundant extract_server_name

removed from server.js since upstream master branch took in this code.