This fixes the path to source files in some unit tests and allows
to get rid of a few duplicate lines.

migration.

* Center font

current canvas. This is useful to export dirty rectangles. Accordingly,
add caca_import_area_from_memory() and caca_import_area_from_file().

their crap all over the place. There is still caca-sharp/obj
that it insists on creating (reported as Connect ID 301965).

on Win64, including the .NET projects.

play with the Windows port, there is a 90-day evaluation version
available for free on the Microsoft website.

code for clarity.

split is rendered moot by the plugin system: when enabled, binaries do
not link directly with libX11 or libGL. I hope this is a step towards
more consisteny and clarity.

* Synchronise parameter types in the C++ bindings with the C API.

* Use size_t and ssize_t where appropriate.

prototypes. As they are equivalent, this does not break the ABI.