Merge pull request #33 from stevegt/master

add lifetime_stats to Makefile; include UM2 in board type 72 comment
Fix various print startup issues: move to old e coord during bed raise; excessively fast priming; remembering retraction status from previous prints; not doing a large retraction when prints complete normally. Also set the default for PLA bed to 60º.
Merge pull request #34 from illuminarti/master

Fix various print startup issues
Small fix after #34, and added some comments to explain a few things better. Thanks Illuminarti
Bug fix after #34
Version 14.06.2