BugFix search from date type field

For Vector source type, the search filter on column of date type don't work because the object of type DateTime is send to the prepareStringForLikeCompare function.
BugFix search from date type field

My precedent patch works only with a column of type dateTime. This commit is for the both columns of type date and dateTime.
BugFix search from date type field
Merge pull request #377 from Flofr/patch-1

BugFix search from date type field