updated gitignore file
removed generated elf and object files from the repository
ignored the generated elf files
fix: static class member MAX_DATA_ENTRIES is not defined -> linker error

Static class members usually have to be defined explicitly which plays not
well with header only libraries. Moving the constant into the ELFIO scope
works around that problem.

The problem only shows up at -O0. Higher optimisations levels manage to
completely remove the references to the static member.
fixed a few warnings (signed-unsigned comparisions, unused param)
fix: make segment loading similar to readelf's algorithm

ALLOC sections are now matched against the virtual address space of
the segment. Non ALLOC sections still use the offset approach.
rewrote the segment save logic to not only care about alignment

The initial implementation only made sure that all sections and segments
are properly aligned. This is enough for simple embedded applications
but can not deal with more complex layouts.

The new implementation should be more generic given that it respects the
virtual addresses of the individual sections.

One thing which is currently not supported by this rewrite are segments
which contain the program/segment header or even the whole elf header.
changed order in which the sections are emitted

The fact that segments can contain header information as well as
sections requires that sections within segments are emitted first.
separated layout generation and saving

Many example elfs (hello_32, hello_64, asm ...) require that the
first section directly follows the program header table. The
section header is then placed between segments or at the end.

This change prepares the late placement of section header table.
move the section table to the end of the elf file
special support for PHDR segments and segments which include the elf header

Only elf files with strange GNU_RELRO segments fail the load, save, cycle.

It would maybe a good idea to separate the layout functionality from the
current save. The current coupling of layout and save make it
impossible to build layouts which contain the elf header via the public
API.
Use boost library version 1.57.0