The +t_obs parameter was confusing for users since it effectively
overwrote the observation time in input coordinates. To make it more clear
what is the operation is doing, users are now required to directly specify
the time span for which they wish to apply a given deformation. The parameter
+dt has been added for that purpose. The new parameter is mutually
exclusive with +t_epoch. +dt is used when deformation
for a set amount of time is needed and +t_epoch is used (in
conjunction with the observation time of the input coordinate) when
deformation from a specific epoch to the observation time is needed.

Changed the direction of dt-calculation to follow the same convention as
helmert. Changed from dt = t_c - t_obs to dt = t_obs - t_c, which
effectively reverses the direction of the operation. Existing projstrings
using deformation can simply reverse the direction of the operation to
achieve the same results as before this commit.

Temporal gridshifts allow [h|v]gridshift operations to be used as step functions
in a pipeline. This is useful in transformations dealing with deformations caused
by earthquakes.

See the included documentation for details.

When transforming coordinates outside the grid model the deformation
operation failed spectatularly. This is now fixed by checking that the
coordinate is inside the grid. If it isn't an error is returned and a
debugging log message is issued.

Closes #934

* Free format now in cmd lines, in gie, and in init files

* Corrected handling of defaults

* Add demo of integrated definition and validation

* Repair stack-smashing memmove in get_init

* repair paralist corruption, clean up debug output

* Install test files for nmake builds

* Add many improvements following suggestions by @schwehr

* Be consistent in requiring lower case everywhere in gie.c

Also, this Fixes #703 and Fixes #697 

The initial approach taken in the deformation operation was not
geodetically sound. The deformation model grids were required
to be indexed in lat/long space with the velocities in the grids
being in cartesian space. This is quite confusing and it is not
a normal way of making deformation models. The usual approach is
to keep everything in the east, north, up, or ENU, space. We adopt
that tradition in this commit. The velocities are still applied in
cartesian space which requires that the grid-velocities are
converted from ENU space to cartesian space. As a consequence of
this change the operation is changed so that it only works in full
3D mode. That is, both horizontal and vertical grids need to be
applied.

The inverse operation is changed slightly to accommodate the
now fully 3D transformation. In it's present form it is a
modification to the original algorithm that also includes the
vertical component in the iteration. This is necessary to get a
proper mapping from ENU to cartesian space in the loop. The
vertical component is overwritten with the initial z-correction
at the end of the loop. This approach is not completely accurate
and will introduce errors, especially when doing many roundtrip
calculations, but it seems to be good enough for a few roundtrips.

The PJ_ENU data type is re-introduced to better communicate the
what state the grid corrections are in throughout the code.

* Poder dual autochecking implementation
* Debugging aid: Improvements in PJ_vgridshift.c and gie.c

* Most likely, the bugbeing tripped is in the gridshift code, so. uncomment suspicious lines in deformation.gie and merge this to support the debugging effort