#178 layer default obs not accessible via R<<

[Michele Gubian]

hi James,

the following is a seg fault I get on the latest lazyNut if I try to access a default obs via R<<. The reproducible example below shows that the problem is actually on default obs, and not on any dataframe, and that the default obs actually work fine, it's only the access through R that causes a crash.
I am on revision 1558. This bug was not there at revision 1534 (the one I still use on another linux PC because of old notation scripts still in use etc.). This bug is there both on Windows and on linux.
Thanks in advance,
Michele

create model ia
quietly ia load Models/ia/ia.eNm
quietly ia stage
(ia::letters default_observer) enable
quietly present step stimulus=a stimulus_duration=10

R << print(eN['ia::vocab'][1:10,])

(ia::letters default_observer) get 1-5 1-5

R << print(eN['(ia::letters default_observer)'][1:5,1:5])
CRASH HERE