Also remove Meter:: versions of related methods, because they are not necessary. We
only need metrical information for operations like ::round_to_bar()
pbd/i18n.h MUST NEVER be included from header files and always be
the last include. This is because `_` is declared other headers
notably boost and some apple headers.
leading to issues like
../libs/pbd/gettext.h:58:27: error: expected unqualified-id before ‘const’
58 | # define gettext(Msgid) ((const char *) (Msgid))