Paragraph 12.8/15 of the C++11 Standard:

The implicitly-defined copy/move constructor for a non-union class X
performs a memberwise copy/move of its bases and members

There is finally only one FunctionProvider, all specializations are gone.
The price for this is one additional line in all functions that should be
provided which is acceptable. See the added documentation of
FunctionProvider on how to proceed for new functions. The only drawback is
that there are still four places in functions.hh that need to be touched.
This is left as an exercise for someone who fancies static loops over tuple
types (not a tuple object), I am too tired now... :)

* use Common::FieldVector in ctor (is convertible from Dune::FieldVector
  and std::vector)
* forbid assignment

refs #282

refs #282

this requires fixing by @ftalbrecht

[functions.checkerboard] read values as scalar values (old behavior, reading of values as vectors lead to lexical_cast error)

Revert "[functions.checkerboard] use GlobalFunctionInterface instead of LocalizableFunctionInterface"

This reverts commit b60b99d8b1a395c3306dcc6f57986a07e4e2181c.

-rename namespace Function to Functions
-rename class Functions to FunctionsProvider

* removed typename ... template from the ...EntityType typedefs
* leave only the typedefs in interfaces.hh and use them
  everywhere
* some cleanup/whitespace changes

* since building the lib costs 5 minutes
  and the resulting lib is about 180MB
  your have to define
    -DDUNE_STUFF_FUNCTIONS_TO_LIB
  if you want to have the functions in the
  libdunestuff