* function get_entry_from_elabid moved to the top to be used by classes
* class Layers renamed Layer
* class Layer expanded and completed with all NeXus-needed metadata
* classes improved with "quality" error management
* class Material added, for now it fetches just compound_elabid and
compund chemical formula (as attribute and method respectively)
* class Material has get_compound() method which needs some commenting
* DEBUG MODE improved to cover all cases: layer, sample, substr. and pld
target; creates a new shortcut for prompting (read line 147)
* removed herobrine (fuck i'm old aren't i)
