Txt2Tags reader: Header is now parsed only if standalone flag is set
Txt2Tags Reader: Parse Meta information

The header is now parsed as meta information. The first line is the
`title`, the second is the `author` and third line is the `date`.
Txt2Tags Reader: Corrected formatting of %%mtime macro
Txt2Tags Reader: Fixed crash when reading from stdin
Merge pull request #1553 from mpickering/master

Txt2Tags reader: Header is now parsed only if standalone flag is set
Fixed --self-contained with Windows paths.

Previously C:\foo.js was being wrongly interpreted as a URI.
Closes #1558.
Docx writer:  Bibliography entries get Bibliography style.

Closes #1559.
Fix build dependencies for the trypandoc flag.

Build dependencies of the trypandoc executable are required, regardless of the
trypandoc flag was set to either True or False.  Correct package description
to make them truly optional.
Capitalized Build-Depends for consistency.
Merge from upstream.