Hide private functions in shared library. Export functionality for utilities.

Hide private functions in shared library. Export functionality for utilities.

Borrowing header stuff written for cairo, fontconfig now exposes in the
shared library only the symbols which are included in the public header
files. All private symbols are hidden using suitable compiler directives.

A few new public functions were required for the fontconfig utility programs
(fc-cat and fc-cache) so those were added, bumping the .so minor version number
in the process.