[source] Drop source mapping handling
It was only used by the cwxmlparser which has been deleted. This is too complex
for litle benefit, we don't want to maintain that in cubicweb.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/html/index.html
Files: /usr/share/doc/cubicweb-documentation/html/*