* detect mimetypes from filenames for all text files
* fixed non-filename based StaticArticle
* enable rewriting of links in poster attribute of audio element
* added find_language_in() and find_language_in_file() to get language from HTML content and HTML file respectively
* add a mime mapping to deal with inconsistencies in mimetypes detected by magic on different platforms
* convert_image signature changed:
* `target_format` positional argument removed. Replaced with optionnal `fmt` key of keyword arguments.
* `colorspace` optionnal positional argument removed. Replaced with optionnal `colorspace` key of keyword arguments.
* prevent rewriting of links with special schemes `mailto`, 'tel', etc. in HTML links rewriting
* replaced `imaging` module with exploded `image` module (`convertion`, `probing`, `transformation`)
* changed `create_favicon()` param names (`source_image` -> `src`, `dest_ico` -> `dst`)
* changed `save_image()` param names (`image` -> `src`)
* changed `get_colors()` param names (`image_path` -> `src`)
* changed `resize_image()` param names (`fpath` -> `src`)