Fix note section handling

[jethrogb]

There are several issues with note sections:

1. There are currently not supported in 32-bit ELF files, but as far as I know, the parsing of note sections in 32-bit and 64-bit ELF files is exactly the same. confusing comment here and documentation here
2. A note section can contain many notes, not just the one at the start of the section.
3. There is no way to obtain the note type, but the spec says you have to check both the name and the type before interpreting a note.