prepare package structure for blob doc level expressions
Merge pull request #767 from crate/l/restructure-doc-expressions

prepare package structure for blob doc level expressions
implement blob doc collector
Merge pull request #770 from crate/l/blob-doc-collector

L/blob doc collector
allow select on blob tables  / integrate BlobDocCollector

Conflicts:
	CHANGES.txt
blob listings: add 'last_modified' expression
Merge pull request #774 from crate/l/blob-last-modified

L/blob last modified
Merge pull request #773 from crate/blob-listings

Blob listings