title: plus sign in solr query is not correctly treated
body: <p>All:</p>
  
  <p>I am new to Solr, when I play with solr example with importing some random document,  I use a search query in q like:</p>
  
  <pre><code>fund+report
  </code></pre>
  
  <p>There is no space between fund and +, and I thought it will search a word "fund+report" in the document, which rarely happen in document, but a lot results return, thequery url is:</p>
  
  <pre><code>http://localhost:8983/solr/collection1/select?q=fund%2Breport&amp;fl=id+filename+%5Bexplain%5D&amp;wt=xml&amp;indent=true
  </code></pre>
  
  <p>I thought Solr treat my query just like:</p>
  
  <pre><code>fund report
  </code></pre>
  
  <p>or</p>
  
  <pre><code>fund OR report
  </code></pre>
  
  <p>Could anyone tell me why solr treat my query like that? And how can I make solr treat fund+report as a single word?</p>
  
  <p>Thanks</p>