Pyexiv2

- Fixed an issue (3) about random crash.
- Updated description.

- Updated description.
- Correct the test cases. Ensure that the operation of reading metadata does not affect the image.

- no longer read `typeName`.
`typeName` is determined by Exiv2 for each metadata.
It was found that reading `typeName` of some metadata could go wrong, causing the program to crash. So, don't read it anymore.

- Methods `read_*()` will return an empty dict, if it didn't get the metadata from the image.
- Add methods `clear_*()`. But once the metadata is cleared, it may not recover completely by pyexiv2.

- Simplified the read methods of class `Image`.
- `Image.read_*()` will return a dict directly.
- Remove six attributes of class `Image`: `.exif_dict`, `.exif_list`, `.iptc_dict`, `.iptc_list`, `.xmp_dict`, `.xmp_list`
- Make sure the path to all project files is in English.
- Rename this project to pyexiv2.

- Be able to read and modify EXIF, IPTC, XMP
- Passed all the test cases on both Linux64 and Windows64
- Can be packaged completely with setup.py
- Detailed instructions are provided in readme.md

(The 1st release was called `pyexiv2`, but it was mistakenly packaged.)