Consider supporting the loading of symbols from external elves

[zardus]

For the megatest, I used Debian's debug symbols, which are shipped in companion ELFs. Most of these open just fine in CLE, but many of them don't. I'm uploading the exceptions for reference.

The files are xz-compressed, and renamed to PNG because github doesn't support xz files. Keep in mind that they may expand a lot.

[rhelmot]

DBG_OPEN_FAIL-AttributeError should also contain #210

[rhelmot]

DBG_OPEN_FAIL-elftools common exceptions ELFParseError should also contain #213

[rhelmot]

eliben/pyelftools#287 seems to fix every single one of these. Do we want to close this issue for that or leave it open with the goal of being able to actually utilize the debug symbol binaries in conjunction with the actual binaries?

[rhelmot]

Just kidding, two more errors. One is eliben/pyelftools#288 and the other I bugged fish about. question still remains about the purpose of this issue though.