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.

Extended the use of the :option: directive to all currently written
operation doc pages. In the process several more default parameters were
added for easy inclusion in other doc pages.

Expanded the info tables for each operation with "domain", "alias",
"input type" and "output type".

Corrected various errors along the way. Mainly formatting errors and
references to invalid parameters such as +sym in hatano.

Instead of listing the various projection options in a table we write
them as :option: tags instead. This makes it easier to write a more
elaborate description of the parameter. Additionally we can create
"master"-description of commonly used parameters such as +lon_0 and +k_0
and include them where necessary. This is handled in separate files, one
for each common parameters, that are stored in
docs/source/operations/options/.