ConTeXt writer: tag paragraphs

Paragraphs are enclosed by `\startparagraph` and `\stopparagraph`
commands. This ensures better tagging results in PDF output.

src/Text/Pandoc/Writers/ConTeXt.hs

@@ -173,7 +173,7 @@ blockToConTeXt (SimpleFigure attr txt (src, _)) = do
       return $ blankline $$ "\\placefigure" <> label <> braces capt <> img <> blankline
 blockToConTeXt (Para lst) = do
   contents <- inlineListToConTeXt lst
-  return $ contents <> blankline
+  return $ "\\bpar" $$ contents $$ "\\epar" <> blankline
 blockToConTeXt (LineBlock lns) = do
   let emptyToBlankline doc = if isEmpty doc
                              then blankline

test/tables.context

@@ -1,4 +1,6 @@
+\bpar
 Simple table with caption:
+\epar
 
 \startplacetable[title={Demonstration of simple table syntax.}]
 \startxtable
@@ -35,7 +37,9 @@ Simple table with caption:
 \stopxtable
 \stopplacetable
 
+\bpar
 Simple table without caption:
+\epar
 
 \startplacetable[location=none]
 \startxtable
@@ -72,7 +76,9 @@ Simple table without caption:
 \stopxtable
 \stopplacetable
 
+\bpar
 Simple table indented two spaces:
+\epar
 
 \startplacetable[title={Demonstration of simple table syntax.}]
 \startxtable
@@ -109,7 +115,9 @@ Simple table indented two spaces:
 \stopxtable
 \stopplacetable
 
+\bpar
 Multiline table with caption:
+\epar
 
 \startplacetable[title={Here's the caption. It may span multiple lines.}]
 \startxtable
@@ -142,7 +150,9 @@ blank line between rows. \stopxcell
 \stopxtable
 \stopplacetable
 
+\bpar
 Multiline table without caption:
+\epar
 
 \startplacetable[location=none]
 \startxtable
@@ -175,7 +185,9 @@ blank line between rows. \stopxcell
 \stopxtable
 \stopplacetable
 
+\bpar
 Table without column headers:
+\epar
 
 \startplacetable[location=none]
 \startxtable
@@ -204,7 +216,9 @@ Table without column headers:
 \stopxtable
 \stopplacetable
 
+\bpar
 Multiline table without column headers:
+\epar
 
 \startplacetable[location=none]
 \startxtable