versioning all symbols in the shared library.

Slony 2.2 allows multiple versions of the shared library to be exist
on the filesystem($libdir) at once.  This means they can be loaded
into the same backend at once, but we need to ensure that the
exported symbols are unique

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=slony1-engine.git;a=commitdiff;h=df50a63646f1962a40d384bf628671729fb81e36

Modified Files
--------------
config.h.in                  |    1 +
config_msvc.h                |    1 +
src/backend/slony1_funcs.c   |  123 ++++++++++++++++++++++--------------------
src/backend/slony1_funcs.def |   26 ++++-----
src/backend/slony1_funcs.sql |   42 +++++++--------
src/slonik/slonik.c          |    8 ++-
6 files changed, 108 insertions(+), 93 deletions(-)