The ASCII STL import was made more tolerant to non-standard input format, namely: 1) Whitespaces are allowed at the end of lines 2) A freeform is allowed after "endloop", "endfacet" and "endsolid", if separated from the keyword by a whitespace. Some ASCII STL exporters likely add their annotations in there.
The ASCII STL import was made more tolerant to non-standard input format,
namely:
1) Whitespaces are allowed at the end of lines
2) A freeform is allowed after "endloop", "endfacet" and "endsolid", if separated
from the keyword by a whitespace. Some ASCII STL exporters likely add their
annotations in there.

Fixes "Error on importing stl" #2813

prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r