[PATCΗ] Quoted values in squid.conf

This patch :

- adds support for quoted values in the entire squid.conf

- warn about or prohibit values that can no longer be interpreted as
either quoted strings or simple tokens

- support file:"path/to/file.name" syntax to load external configuration
files

- support macros in "double quoted" values

- support 'single quoted' values that do not expand macros

- replaces the strtok() calls with calls to the new
ConfigParser::NextToken()

- modify strtokFile to use new ConfigParser::NextToken()

- Add the new configuration_includes_quoted_values configuration option,
to control the squid parser behaviour. If set to on Squid will recognize
each "quoted string" after a configuration directive as a single parameter.

This is a Measurement Factory project