Fixes: #763

* Call trans func of same dimensionality as input in gie

* Refactor prep/fin code for pj_fwd/pj_inv 2D,3D,4D

* Remove prime meridian handling from pj_transform (now handled in pj_fwd_prepare/pj_inv_finalize)

* Introduce prep/fin skips, mostly in support of axisswap and pipeline drivers

* Refactor fwd/inv subsystem

* pj_transform: Let pj_fwd/inv handle scaling

* Let pj_fwd/inv3d fall back to 2D eventually

Central conic projection implemented as 'ccon'.

* Introduce geodetic-geocentric conversions, as PJ_xxx style conversion step and as API entry points

* minor improvements and minor bug squashing

* Removed remaining traces of the builtin selftest system. Moved all functionality to test/gie

* Updated Appveyor and Travis build scripts

* Another appveyor script update

Kinematic deformation models are used in some geodetic transformations.
This commit introduces the ability to do transformations involving a
gridded deformation/velocity model. For practical reasons a gridded deformation
model needs to be split into two seperate files, one for the horizontal
components and one for the vertical component. For this we use formats
already known to PROJ.4, namely the CTable/CTable2 and the GTX formats.
Grids are specified in the proj-string with +xy_grids and +z_grids.
Grid values are expected to be in m/year. The kinematic part of the
operation is controlled by the +t_epoch parameter, which is the central
epoch of the transformation. An observation epoch is also needed. It can
be specified either in the PJ_OBS input as the fourth element in the
coordinate, or in the proj-string with +t_obs. If +t_obs is present in
the proj-string it takes presedence over the value in the PJ_OBS
coordinate.

* Remove PJ_OBS from the API surface, rename pj_obs_api.c to pj_4D_api.c

* Repair proj.def

Touch up configuration files to support gie