Add cmake support for BSB, DTED, ESAT, ERS, SDTS and XPM
Merge pull request #19 from simonsonc/various

Add cmake support for BSB, DTED, ESAT, ERS, SDTS and XPM
Add cmake support for GME, GMT, GPSTrackMaker, HTF, DGN, PGDump drivers
Fixed cmake support for XPM and ENVISAT drivers