On little-endian hosts, stl_internal_reverse_quads will be called before
it is declared. Move the declaration up to the beginning of the file to
fix build breakage seen on an s390x host.
Fix of 2.1.0-rc: Loading MMU STL's results in object placement off the plater (#2868)
It has been broken with 9abef2241d188d0cc0892bc3070d7360749c2702
when trying to fix "Error on importing stl" #2813
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
