make ParserItems always defaultable

i.e. remove the defaultSet() method and its friends. this is required
to be able to specify defaults in DATA items like grid properties or
saturation tables. e.g.

SGL
10*0.1 10* 10*0.2 /

would not be possible without this. If no meaningful default for an
item is defined, float and double items get NaN, int items get -1 and
string ones get an empty string. The hope is that if these values get
used in the simulation, they will make the result obviously
incorrect. (Whether a data point of an item was defaulted can be
queried using item->defaultApplied(index).)
add more explicit unit test for defaulted deck items

(the ParserItemTests already have one (Scan_All_WithDefaults) but a
second one won't hurt...)
add some defaulted values to the unit test of PVTG
remove the "value status" concept from deck items

I know it was only added recently, but all of the "setInDeck()" calls
can now be substituted by a combination of item->size() and
item->defaultApplied(index)...
extend "StarToken" class and rename it to "RepetitionToken"

that's because not every token which contains a star represents an repetion, e.g.

'123*456'

(with the quotes) is a string...