* util/ioprocsvec.h: Fixed truncating when a write doesn't reach the end
of stream. [F.Ulivi]
* floptool.cpp: Fixed reversed error checking logic. [F.Ulivi]
* Fixed SUBTARGET=tiny build (required Sega encrypted CPUs to be added).
Added more modern generic I/O interfaces with implementation backed by stdio, osd_file and core_file, replacing io_generic. Also replaced core_file's build-in zlib compression with a filter.
unzip.cpp, un7z.cpp: Added option to supply abstract I/O interface rather than filename.
Converted osd_file, core_file, archive_file, chd_file and device_image_interface to use std::error_condition rather than their own error enums.
Allow mounting TI-99 RPK from inside archives.
