Add required quotes around 'q1' in README example

The example in the README:

    (query q1 {:subj "http://dott.com/mysubject"})

 causes the following error:

    CompilerException java.lang.RuntimeException: Unable to resolve symbol: q1 in this context, compiling:(NO_SOURCE_PATH:1) 

This is because the README does not wrap `q1` in quotes, as is done in the tests. After I added these quotes, the example works as expected.