title: im4java throws FileNotFoundException error
body: <p>I need to use ImageMagic in my java project.
  I already installed ImageMagic-7.0.3 on Windows 10
  (command line works fine)</p>
  
  <p>Then, i added dependency to im4java in maven file. When i try to do some action like:</p>
  
  <pre><code>public static void main(String[] args) {
  
  String imPath="C:\\Program Files\\ImageMagick-7.0.3-Q16";
  ConvertCmd cmd = new ConvertCmd();
  cmd.setSearchPath(imPath);
  IMOperation op = new IMOperation();
  op.addImage("biuro.jpg");
  op.negate();
  op.addImage("biuro_new.jpg");
  
  
  try {
      cmd.run(op);
  } catch (IOException e) {
      e.printStackTrace();
  } catch (InterruptedException e) {
      e.printStackTrace();
  } catch (IM4JavaException e) {
      e.printStackTrace();
  }
  
  System.out.println("works");
  
  }
  </code></pre>
  
  <p>i get following error</p>
  
  <pre><code>org.im4java.core.CommandException: java.io.FileNotFoundException: convert
      at org.im4java.core.ImageCommand.run(ImageCommand.java:219)
      at Main.main(Main.java:30)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
  Caused by: java.io.FileNotFoundException: convert
      at org.im4java.process.ProcessStarter.searchForCmd(ProcessStarter.java:661)
      at org.im4java.process.ProcessStarter.startProcess(ProcessStarter.java:399)
      at org.im4java.process.ProcessStarter.run(ProcessStarter.java:312)
      at org.im4java.core.ImageCommand.run(ImageCommand.java:215)
      ... 6 more
  </code></pre>