Convert all upscaling programs to new pinch behaviour.

This means that PINCH must be used in the input deck,
whereas before, z_tolerance was available as a program
parameter (but only for some programs). A benefit is that
all programs will now uniformly accept PINCH in the input
decks.
Merge pull request #125 from atgeirr/use-pinch

Convert all upscaling programs to new pinch behaviour.
Upscaling utilities: Use raw property vectors where appropriate

We need access to the raw, unconverted property vectors to use the
existing algorithm for defining (e.g.,) capillary pressure ranges.
This subtle point was missed during the initial transition to using
the opm-parser module for input handling.
Upscaling utilities: Don't hard-code numeric conversion factor

This commit replaces the hard-coded conversion factor from mD to
m**2 (metres squared) with an expression based on the Units.hpp
facility of module opm-core.

Note: This may introduce slight changes to the upscaling result due
to reduced rounding error in the unit conversions.