Extract addMembersFromSpace to function.
Extract addMembersFromSpace to function.

This a) ameliorates some endless right shifting, b) adjusts
the code so that the xhr's are done sequentially (but still
asynch) to avoid confusing the bag and recipe policies. See:

    http://cdent.tiddlyspace.com/20120809
    http://cdent.tiddlyspace.com/20120812

for additional context. Fixes (or should):

    https://github.com/TiddlySpace/tiddlyspace/issues/983

TiddlySpace/ts.js