Shared build-system files for (some) parts of Taler.

A repository using these build-system files should be structured as follows:

<my-repository.git>
- bootstrap (copied/adjusted from bootstrap.template)
- build-system (directory containing build system "stuff")
--| configure.py (copied/adjusted from bootstrap.template)
--| taler-build-scripts (git submodule of taler-build-scripts)
--| Makefile

Makefile and configure.py can also be placed directly into the root of the
repository.  However, this might lead to errors when "make" can be invoked
before bootstrap and configure has been done.


directory structure:
--------------------

conf:
- contains mixed configuration data, mostly for linters and editors

sh:
- contains shell script code in reusable, importable pieces,
  usually one function per file and files named after their
  function.
  the sh/lib.sh folder contains library code.
  the sh/bin.sh folder contains executable scripts which can be
  used for various functions.
  Current caveat: the files all have to be included. shell independent
  detection of real pathnames is tricky.
