Log Message:
ethemes: update installation locations

wm/enlightenment now installs under "e16" directories, not
"enlightenment", including its default theme. Change this package to
match the expected location, and, while here, fix permissions on the
installed files. (The theme format used by Enlightenment >= 17 is
incompatible with that used by E16, so these themes are only relevant
to E16.)

(TBD: these themes are rather old; there are newer supplementary E16
themes provided upstream that should be added, but I'm leaving that for
a separate pass.)