Version 5 lineprogram header (#411)

Version 5 lineprogram header (#411)

* Version 5 lineprogram header, take 1

* Readelf/decodedline formatting fix

* DWARF 5 fields None, not missing

* Comment

* Sample binary

* Dump unit type in readelf info

* More languages described

* Describing form_line_strp

* Basic support for GNU_PROPERTY_X86_ISA_1

* Readelf decodedline format fixes to match with DWARF5

* Readelf test shorted out for the file/test where a bug in GNU readelf manifests, see PR #411.

* Newline :)

* Readelf' language names matched against binutils

* Comment about lineprogram files and directories

* GNU binutils bug worked around in a slightly less disturbing way - patched the binary, left a comment in the test script.

* Examples autotest no longer fails on Windows over expected path format

* Autotest fix

* Typo

* Windows compatibility, take 2

* No pathlib on Python 2

Co-authored-by: Seva Alekseyev <sevaa@nih.gov>