PDF viewer detection incorrect in OSX

[Xavier (Open ERP)]

In the printer module (printer/printer.py), the PDF file opener is defined as `os.system('/usr/bin/open -a Preview '`. This is incorrect when the user does *not* want to open PDF files with Preview and configured his OS otherwise.

/usr/bin/open without any argument but the file name explicitly uses the default (os default or file default) application for the file, the viewer therefore shouldn't be hardcoded to Preview.

Also, specifying the full path to open shouldn't be necessary.

[Xavier (Open ERP) (xmo-deactivatedaccount)]

The OS detection routine is also incorrect: it should use sys.platform whose behavior is clearly documented (and includes osx as 'darwin') instead of os.uname(). Furthermore sys.platform is available under Windows so the os.name != 'nt' wouldn't be necessary anymore

[Samantha (samantha-z-mathews)]

whathas been fixed and committed?
please clarify.

[Xavier (Open ERP) (xmo-deactivatedaccount)]

printer.py has been modified to call `open` on the PDF file without mandating preview (it was `open -a Preview` before) and removing the `/usr/bin` prefix which shouldn't be useful, the test is now performed on `platform.system()` instead of combinations of `os.name` and `os.uname()`.

On 5.0 this is part of 5.0.12.

Also, for 6.x, the Linux detection/opening was altered: it now calls xdg-open, gnome-open and see (in that order) to try to get the system's default PDF reader (in the fashion of Window's `startfile` or OSX's `open`).