Note: 
  If you are using qextserialport-XXX.tar.gz, the qesp.qch and
  html files have been provided.
  Open the file "html/index.html" using your web browser.
  Or integrated the "html/qesp.qch" into your QtCreator.
== How to generate help files? ==
Simply run following commands at toplevel directory.
    qmake
    make docs
Or run the following command at this directory
    qdoc3 qextserialport.qdocconf
Then a folder called "html" will be generated. 
Open the file "html/index.html" using your web browser.
== How to integrated into Qt Creator or Qt Assistant? ==
Once the html files are generated. run following commands
   cd doc/html
   qhelpgenerator qesp.qhp
A file called "qesp.qch" will be generated.
For Qt Assistant: 
   Edit ==> Preferences ==>  Documentations ==> Add...
For Qt Creator
   Tools ==> Options ==> Help ==> Documentations ==> Add...