KBB file: numeric attribute value stored only as string

[amnonma]

@dehilsterlexis
While the NLP++ KB can store numeric attribute values, the KBB file stores numbers only as strings.
Properly, string values should have double quotes on them, to distinguish from non-string attribute values like num and float.
At the very least, VT/NLP++ user needs to be warned that every value in a KBB file is a string.
While here, a way to store concept pointers as values should also be possible in a KBB file.

[amnonma]

There may be a long-standing bug in NLP++ KBs regarding string versus integer values.
Seems numbers can be stored as strings, but then must be fetched as integers.
Some kind of mess here.

[dehilsterlexis]

@amnonma actually, that should be working. I thought I fixed that a while back. I will check.