sqlparse: Generated Python and PHP snippets allow SQL string breakout through unescaped backslashes

sqlparse is a non-validating SQL parser module for Python. Prior to 0.6.0, sqlparse/filters/output.py fails to escape existing backslashes before quotes in sqlparse.format output_format='python' and output_format='php' and the corresponding sqlformat -l modes, allowing crafted SQL to terminate the generated string and inject Python or PHP code when a downstream consumer executes or imports the generated source. This issue is fixed in version 0.6.0.