POD

Function xhtml - Management of borders: bugfix.
Function xhtml - CSS attributes expressed in percentages: fix.
Function xhtml - Reading CSS attributes: fixes.
Function xhtml - Management of table margins: fix.
Function xhtml - Added the possibility to use the pretty printer to inject chunks of Python code within produced results.
Communication with LibreOffice (LO) via UNO: removed a code leading to the LO process using 100% CPU forever.
Added Renderer parameter csvOptions allowing to customize CSV export, when the POD result is a CSV file.
Removed obsolete function test from the POD context.
More comments in the code and better formatting.