Allow scoped variable names

The existing version of this tag failed on examples where I had scoped variables, such as those below.  I've altered the code to support this, and as far as I can tell all previous examples also continue to work.  Please consider this for inclusion in the project?

Below is an example that failed previously, that will now work with these changes

    <cfset loc = {}> 
    <!--- read in the file --->
    <cfset loc.pathToFile = ExpandPath("someExistingFile.xls") /> 
    <cfspreadsheet action="read" 
        src="#loc.pathToFile#"
        query="loc.myQuery" />

    <!--- display query results --->
    <cfdump var="#loc.myQuery#" label="Query With Default Column Names" />`