Added ENgetheadcurve(), ENgetpumptype() and related constants.
Fix ENgetlinkvalue() for EN_MINORLOSS and pumps.
Merge pull request #11 from sdteffen/pumptype

Added ENgetheadcurve(), ENgetpumptype() and related constants.
Merge pull request #12 from sdteffen/pumpEN_MINORLOSS

Fix ENgetlinkvalue() for EN_MINORLOSS and pumps.