New buildfarm client release 4.12

I have released version 4.12 of the buildfarm client.

In addition to numerous bug fixes, it has the following:

* the global option branches_to_build can now be "HEADPLUSLATESTn' for
any single digit n
* there is a new module TestCollateLinuxUTF8
* there is a new module TestDecoding which is enabled by default, (but
does nothing on MSVC systems, where we can't yet run these tests.)
This runs the new contrib test_decoding module, which can't run
under "make installcheck".
* running "perl -cw" on the scripts will now give you failures for
missing perl modules on almost every platform. The only exception
should now be on older Msys systems.
* improvements in the sample config file to make it better organized
and better reflecting of best practice.
* find_typdefs is now supported on OSX

In addition I recently enhanced the HOWTO at
<http://wiki.postgresql.org/wiki/PostgreSQL_Buildfarm_Howto#Using_run_branches.pl>
covering especially best current git practice.

Thanks to Tom Lane for suggestions and complaints which are behind a
number of the improvements and fixes, and for some code for OSX
find_typedefs.

The release is available at
<http://www.pgbuildfarm.org/downloads/releases/build-farm-4_12.tgz>

cheers

andrew