switch naming back from libmapnik2 -> libmapnik (also python)

[springmeyer]

/cc @rcoup, @dpaleino, @artemp for comments.

During the large refactoring push and testing period after merging the mapnik2 codebase into mainline trunk it was very useful for development to ease the ability to run both mapnik 0.7.x and mapnik 2.x together simultaneously, and this was done by adding a 2 to the library name and the python module.

We should now switch back to normal naming for the next release (2.0.1) and all that follow. The reasons are plenty:

• packaging systems know how to handle multiple versions - lets let them do the heavy lifting on this
• we do not anticipate another long period again where simultaneous testing for development like this will be needed
• from source build systems that depend on mapnik should not have to adapt to mapnik2 naming (and mapnik3, 4, etc)
• the namespacing was imperfect (because we did not want to rename the headers to #include </mapnik2/...> as this would have caused a lot of breakages)
• sonaming should be used to handle library naming between different versions not the actual library basename.

The downside of course is that many users in python are now used to doing import mapnik2, but we can reach out to communicate this switch back and hopefully this will be a lesser evil if we move on this now.

[springmeyer]

I'll start with my:

+1 :)

[artemp]

Yes, lets keep it simple :

+1

[dpaleino]

+1 from me too.

[rcoup]

+1 :)

I'd suggest we leave the mapnik2 package as a shim around mapnik for the python bindings, and make it raise a deprecation warning (ie. go back to only having a mapnik package at v3)

[kunitoki]

+1 and +1 for rcoup idea too

[springmeyer]

yep, good idea @rcoup

[artemp]

Done in 14700db
mapnik2 is still available but raises DeprecationWarning

[dpaleino]

ACK, thanks!

I'll wait a release before doing this in Debian too :)