a few complaints /comments from Khaled Hosny

[HinTak]

Look into these at some point, from https://github.com/googlei18n/ufo2ft/issues/195#issuecomment-354578855 , duplicated here:

E | E2101 | There are undefined bits set in fsSelection field Bit(s) 7

(complaining about USE_TYPO_METRICS bit, in the spec since 2008).

or

E | E5400 | The FeatureParams field is not null FeatureList, FeatureRecord27, FeatureTable

(non-null is allowed in the spec since 2000)

or

E | E5700 | The LookupFlag reserved bits are not all set to zero LookupList, Lookup[29]

(complaining about useMarkFilteringSet bit, in the spec since 2010)

[adrientetar]

googlei18n/fontmake#414 also noted that E2003 is obsolete.