Add list of shared libraries and build-ids into rich core
Try to load symbols for libs without build-id into gdb before making a stack trace
Fix gdb detection

Seems rich-core-dumper is invoked with PATH not exported to be seen
by subshells, so 'which' couldn't find 'gdb'.

Also discard zypper output that would be otherwise appended to the
core image.
Merge pull request #4 from xhaakon/stack-trace

[core] Add list of shared libraries and build-ids into rich core