* First round of adding fea output
No format tests but all test files give reasonable output so far.
* Get existing tests working
* Initial tests that work for fea2fea
* Get more tests working
Bug fixes and re-layout some tests to compare with fea2fea output.
Ranges and name parameters are not optimised yet.
* Handle vertical default values in fea2fea
* Hide fea2fea differences in lookupflags
* No reduce() in py3 so use a for loop
Before this change, we had only emitted a SinglePos (GPOS type 1) lookup
for a statement like `pos A' B' 20`; after this change, we always emit a
chain rule even if there is no context. There is a semantic difference if
the rule is preceded by a `ignore pos` statement. Omitting context-free
contextual chains was actually not a (premature) optimization, but an
artifact that came from the representation of glyph patterns.
https://github.com/behdad/fonttools/issues/516
