Fix an unused variable warning. Bug #6582
Remove trailing spaces.
Fix JSON array compact printing.

Fixes bug 7180.

As drive-by fixes, actually test the pretty printer and don't ever
start a new line after a property name.
Log more data in exact roundtrip tests.

This ought to help me track down the test failure  on the msvc12 builder.
Escape newlines and tabs in content when writing XML.

By having them escaped, we prevent their replacement with simple
whitespace when reparsing. Fixes bug 7519.
Merge branch 'develop'.

Merges fixes for bugs 7519, 7180, 6582.