Rename and document lists:zf/2 as lists:filtermap/2

This function is used all over the place in OTP itself and people
sometimes want that functionality, they may as well not reimplement it
themselves.
Merge branch 'dg/win_icon' into pu
Merge branch 'rc/break-out-asserts' into pu
Merge branch 'nm/mnesia_idx_insert_speedup' into pu
Merge branch 'tja/erl_pp_options' into pu
Merge branch 'nox/disambiguate-equal-binary' into pu
Merge branch 'hsv/add_init_to_lists' into pu
Merge branch 'nox/fix-epp-file-attrs' into pu
Merge branch 'nox/fix-silent-rules' into pu
Merge branch 'nox/fix-warnings' into pu
Merge branch 'nox/wide-chars' into pu
Merge branch 'sla/reltool_copy_file_not_owner_fix' into pu
Merge branch 'sla/odbc_in_non_standard_location' into pu
Merge branch 'avi/fix-os-cmd-win' into pu
Merge branch 'nox/lists-filtermap' into pu
Merge branch 'bjorn/fix-encoding' into pu