Fix the finding of a file name in the GNU extension for long names
in GNU archives so the correct location is referenced.
Made the image read and write routines keep reading if not all the
requested data is read or written due to possible signals.
This also adds support to the ELF classes that wrap libelf. While
this is now done and seems to work I will not be using an ELF
file to hold the metadata after all.
The refactoring allows better reuse of the ELF support and cleans up
some hacks from the generic file and archive handling improving the
separation of the file handling from the file format, ie ELF. The
handling of ELF object files and ELF object files inside archives
is cleaner.
The refactor cleaned up the symbol handling where the symbols now
reside in the ELF file object and references are take in symbol
pointer containers and symbol table containers.
The main purpose of the refactor is to allow support for creating
and writing ELF files.
Also added an rtems-syms command where special symbol support
can be added.
