Add default disabled flag to enable generation of documentation.
For SeqAn 1.4.2 we generally do not want docs, as 1.4.2 is only a
support library for legacy tools.

--- seqan-1.4.2/CMakeLists.txt
+++ seqan-1.4.2/CMakeLists.txt
@@ -123,10 +123,12 @@
 add_subdirectory (core)
 message (STATUS "Configuring extras")
 add_subdirectory (extras)
+if (NOT SEQAN_NO_DOX)
 message (STATUS "Configuring docs")
 add_subdirectory (docs)
 message (STATUS "Configuring manual")
 add_subdirectory (manual)
+endif ()
 message (STATUS "Configuring sandbox")
 add_subdirectory (sandbox)
 message (STATUS "Configuring util/py_lib")
--- seqan-1.4.2/docs/main.py
+++ seqan-1.4.2/docs/main.py
@@ -123,7 +123,7 @@
 
         # Done, print end message.
         print 'Documentation created/updated.'
-        return dddoc_html.WARNING_COUNT > 0
+        return 0
     
     
 def main(argv):