[Plplot-devel] Update to C++ bindings and examples

[Andrew R. <an...@co...>]

I've made some more updates to the C++ bindings and also translated
all the C examples into C++ to test the API. 

The patch makes the change so that plinit is no longer called in the
constructor, but instead has to be called explicitly by the user.
This makes it much easier to change settings such as the driver type
and also means command line option parsing works. It does break
compatibility with older versions though.

The patch is a bit large to send to the list but can be downloaded
from
http://www.chiark.greenend.org.uk/~andrewr/plplot-c++-patch-5.2.1

Hopefully this will kickstart people into thinking about using the
C++ API. 

Regards

Andrew