While here, also add check for all (current) unit conversion
constants for METRIC, FIELD, and LAB unit conventions and extend the
existing PVT-M checks to cover effective Kh too.
This also means UnitSystem must be default constructible, which now
makes the default unit system metric. GridProperties must also be
default constructible (a valid 0x0x0 grid with no properties).
This commit adds conversion factors for the ECL LAB unit
conventions--notably Atmospheres for pressures, Hours for time,
Grams for mass, and cubic centimetres for volumes.
Every header is self-contained and includes only what it must to
function, relying on users include what they need in source files,
adopting a pay-what-you-use model (in particular for internal
dependencies).
this is just the result of
```
find -iname "*.[ch]pp" | xargs sed -i "s/ *$//"
find opm/parser/share/keywords -type f | xargs sed -i "s/ *$//"
```
so if it causes conflicts with other patches, the others should get
priority. The rationale behind this patch is that some people tell
their editor to remove white space which leads to larger than
necessary patches...
this requires the possibility of specifying an offset for the SI
conversion because Eclipse in its eternal wisdom chooses to specify
temperatures using degrees Celsius and degrees Fahrenheit instead of
using Kelvin an Rankine...
