Users who want pure readers can still get them; this just affects
the function getReader that looks up a reader based on the format
name.
The point of this change is to make it possible to print warnings
from the parser.
* Added `embed_data_files` flag. (not yet used)
* Shared no longer exports `findDataFile`.
* `readDataFile` now returns a strict bytestring.
* Shared now exports `readDataFileUTF8` which returns a string like
the old `readDataFile`.
* Rewrote modules to use new data file functions and to avoid
using functions from Paths_pandoc directly.
* Remove executable and library flags.
* Expose `Text.Pandoc.XML` and `Text.Pandoc.Biblio`.
* Depend on pandoc library in executable, so we don't recompile
everything.
* Move pandoc.hs from src/ to .
