Remove t/native_pbc/number_8_8_le.pbc; update MANIFEST.

For: github #971
Merge branch 'g971-native-pbc'
Add new tool to speed up the release process: make_upload_commands.pl
Add make_upload_commands.pl to MANIFEST.
Fix codetest failures in make_upload_commands.pl .
Update Changelog with the rest of 5.5.0 changes.
Prepare for the 5.5.0 release.
Prepare for the 5.5.0 release, part 2.
Merge branch 'master' into m0