[Divingduck]

No, they not appears at the end. You have 2 issues

First take a look at postprocess_html.

for h1 in soup.findAll('h1'):
                h1.extract()

The statement push calibre to delete all h1 tags and this means no h1 headings at all.

This is the first time I saw a mixed up sequence and had a little lesson learned on this.
You can move around when you rearrange the section keep_only_tags. Take in the sequence first content-header and then content-content:

    keep_only_tags = [  
                      dict(name='div', attrs={'class': ['content-header'}),
                      dict(name='div', attrs={'class': 'content-content'}),
                      dict(name='article', attrs={'class': 'module article dropShadowBottomCurved'}),
                      dict(name='article', attrs={'class': 'module blog dropShadowBottomCurved'}),
                      ]

But the better way around is to put all similar dict statements in one statement:

    keep_only_tags = [  
                      dict(name='div', attrs={'class': [
                                                'content-content',
                                                'content-header',
                                                        ]}),
                      dict(name='article', attrs={'class': [
                                                'module article dropShadowBottomCurved',
                                                'module blog dropShadowBottomCurved',
                                                            ]}),
                      ]