Minor improvements to CyclicBufferAppender, and tests

LOGBACK-805: DBAppender assumes that caller data is available on the event

This will fix LOGBACK-798 (Leaking jdbc pool connection)

Add gray as a choice for ANSI color escapes.

make Level.toLocationAwareLoggerInteger() static

Fix for http://jira.qos.ch/browse/LOGBACK-463.

Fixing the log "Could not parser [l as an integer"

Now will display the (supposedly) correct one:
"Could not parse [l] as an integer".

This will fix LOGBACK-798 (Leaking jdbc pool connection)

LOGBACK-805: DBAppender assumes that caller data is available on the event

LOGBACK-700 + ImportCustomizer for GafferConfigurator

Added jmxConfigurator method to ConfigurationDelegate which allows overriding the default context name or the entire ObjectName

 The customizer auto-imports commonly used types, packages and Level constants (incl. their lower-cased names as aliases)