Implement <code> blocks in dokuwiki writer (#386)
Don't add entities in <code> blocks in dokuwiki writer (#386)
Fixed inlined code in dokuwiki writer (#386)
Add extra pair of test files for dokuwiki writer (#386)

I've found some incorrect behaviours with the dokuwiki output, for which
extra test cases will be needed - that aren't covered by the standard 
pandoc test input files.
Add more tests for dokuwiki writer (#386)
Nasty hack to stop C comments in inline code becoming italics in dokuwiki writer (#386)
Treat inline code blocks like <code> instead of <tt> in dokuwiki writer (#386)

Done because I noticed that in the Autolinks section of writer.dokuwiki, the URL in inlined code was getting auto-linked, when it wasn't supposed to.

This also meant that any inline code examples that had text that looked like dokuwiki syntax could break the formatting of later text.
Stop plain text // becoming an italic marker in dokuwiki writer (#386)

When the original document had text containing //, this was previously
included, unchanged, in the dokuwiki output, and this interacted badly
with later, intended, formating text.
Stop plain text ** and __ becoming formatting in dokuwiki writer (#386)
Removed unnecessary line-break after hard break in dokuwiki writer (#386)
Bullet and ordered lists now always simple in dokuwiki writer (#386)
Fix some warnings in dokuwiki writer (#386)