copy the fixed protocol headers to the target directory

def copy_fixed_headers(directory, xml):
    '''copy the fixed protocol headers to the target directory'''
    import shutil
    hlist = [ 'Parser.java', 'Messages/MAVLinkMessage.java', 'Messages/MAVLinkPayload.java', 'Messages/MAVLinkStats.java' ]
    basepath = os.path.dirname(os.path.realpath(__file__))
    srcpath = os.path.join(basepath, 'java/lib')
    print("Copying fixed headers")
    for h in hlist:
        src = os.path.realpath(os.path.join(srcpath, h))
        dest = os.path.realpath(os.path.join(directory, h))
        if src == dest:
            continue
        destdir = os.path.realpath(os.path.join(directory, 'Messages'))
        try:
            os.makedirs(destdir)
        except:
            print("Not re-creating Messages directory")
        shutil.copy(src, dest)