HTML writer: don't process pars with empty RawInline, fixes #1040

[mb21]

No description provided.

[jgm]

The build failures due to happy should be fixed by the latest update to .travis.yml.
But there is one warning that should be fixed before we merge:

/home/travis/build/jgm/pandoc/src/Text/Pandoc/Writers/HTML.hs:460:29: warning: [-Wunused-matches]
    Defined but not used: ‘str’

[mb21]

of course... btw, I'm getting quite a few warnings in the markdown reader with stack build --ghc-options="-Wall"

.../Readers/Markdown.hs:1891:3: warning: [-Wunused-do-bind]
A do-notation statement discarded a result of type ‘String’

[jgm]

I always use "-Wall -fno-warn-unused-do-bind".

[jgm]

Note also that the default ghc options (from the cabal file) include -Wall -fno-warn-unused-do-bind. So you shouldn't need to specify ghc-options separately on stack.

[mb21]

ah right, then I must have overlooked it...

[mb21]

(fixed and rebased btw)

[jgm]

OK, I see the problem with the builds that failed. Fixed now I think.
I'll merge this, thanks!