PyYAML's scanner is not written to handle Python's unicode literal
strings, since they are not part of the YAML spec. With all strings
loaded in the YAML context now being unicode types, this causes errors
when scanning the document to construct the next node. The unicode
string literal is misidentified as a plain scalar and any colons within
it are interpreted as delimiting a mapping node. Since no whitespace appears
after the colon, this causes scanning error.
To fix it, we check for this scanning error and reset the scanner's
position and check if the first char is the "u" prefix. If so, and if
the following char is a quote, then we attempt to scan for a string
literal instead.
PyYAML works with and without bytestrings on PY3, and Python 3 can read
all of the test data as regular strings, so bytestrings are unnecessary
here.
This also adds use of textwrap.dedent to make the YAML easier to read,
so it can be indented away from the far left side of the line.
