corrected bug in instantiator, realized we need to load resources
otherwise findTopFrom returns entities that shouldn't be considered top
override writeNewResourceDescriptions rather than doUpdate in builder
added comment for an improvement in the future
properly implemented NodeIterator#remove and Node#delete
solved bug where mapping of old context were kept
corrected bug in instantiator: was using the old version of entities
This is the first commit in which partial instantiation can be said to
work (as long as you don't use bundles). The code could do with some
cleaning, because it appears to me to be unnecessarily complicated,
especially the way mappings are updated.