Delegated in all ctors without time to those with time as parameter.

Using the new "util::getTime()" function all classes with 2 ctors, one with time and without time as parameter, that are otherwise similar, the timeless ctors now delegate to the ctors with time parameter.
Added some notes to "ReferenceList" class.
Fixed SimpleTag::createRepresentation to not allow Indexed LinkType

Closes issue #163
Merge pull request #165 from balint42/delegate_ctors

Delegated in all ctors without time to those with time as parameter.
Merge pull request #166 from balint42/fix_simpletag_linktype

Fixed SimpleTag::createRepresentation to not allow Indexed LinkType
unit scale estimation works correctly now
Merge pull request #168 from jgrewe/units

unit scale estimation works correctly now