GH-76 Consider ecl type precision underscore delimiter
- Update trailing numeric patern to include possible underscore
  followed by 1 or more numeric chars
- Add missing ECL REAL to SQL REAL type mapping

Signed-off-by: Rodrigo Pastrana <Rodrigo.Pastrana@lexisnexis.com>
Merge pull request #77 from rpastrana/gh-76-ecl2sqlmapunderscore

GH-76 Consider ecl type precision underscore delimiter