Bug 1004331 - Handle unexpected excess files in get_about_memory.py
Bug 1004342 - Fix get_about_memory.py crash when printing timeout error message.

The operator for combining sets is `|`, not `+`.
Merge pull request #341 from jld/about-memory-set-union

Bug 1004342 - Fix get_about_memory.py crash when printing timeout error message. r=dhylands
Merge pull request #342 from jld/about-memory-excess-files

Bug 1004331 - Handle unexpected excess files in get_about_memory.py. r=dhylands
add MIPS support