title: xml changing the value of an attribute
body: <p>I have the following text in xml file: </p>
  
  <pre><code>&lt;Config Builder="LP Wizard"&gt;
      &lt;Libraries&gt;
          &lt;Library Name="XCAMSource"/&gt;
      &lt;/Libraries&gt;
      &lt;InputFormats&gt;
          &lt;XCAM Format="XCAM" LibraryDirectory="C:\XCAM"/&gt;
      &lt;/InputFormats&gt;
      &lt;OutputFormats&gt;
          &lt;Pads Version="PADS 5.0" ExportAscii="false" LibraryGenerate="true" ExtendedLayers="false" AlphaLoc="PART TYPE" Format="PADS" LibraryDirectory="c:\XCAM\OUTPUT" DirectoryStructure="false" Units="Millimeters" NewCodeVersion="false" usrLayerNameElecT="1" usrLayerNameElecB="2" usrLayerNameSilk="26" usrLayerNameSilkb="29" usrLayerNameCY="20" usrLayerName3D="25" usrLayerNameAssy="27" usrLayerNameAssyb="30" usrLayerNamePmask="23" usrLayerNameSmask="21" usrLayerNameSmaskb="28" DirectImport="false"/&gt;
      &lt;/OutputFormats&gt;
  &lt;/Config&gt;
  </code></pre>
  
  <p>I need to change the text "C:\XCAM" that sits under <code>LibraryDirectory=</code>.</p>
  
  <p>What is the smart way to do so, I just dont want to string search for <code>LibraryDirectory=</code>
  and then search for first and last " and then to change the text betweenthem.</p>