Fix a TypeError, str vs unicode.

E: 139836956702464 21:25:09 Traceback (most recent call last):
  File "./picard/album.py", line 133, in _parse_release
    run_album_metadata_processors(self, m, release_node)
  File "./picard/metadata.py", line 334, in run_album_metadata_processors
    processor(tagger, metadata, release)
  File "./picard/coverart.py", line 178, in coverart
    config.setting["caa_image_types"].split())
TypeError: descriptor 'lower' requires a 'unicode' object but received a 'str'
Merge pull request #135 from zas/unicode_str_error

Fix a TypeError, str vs unicode.
Move source images (.psd, .svg) from images to img-src directory
Add script to generate picard.qrc from png images in images directory
Make compile.py runnable from anywhere and importable.
Mark compile.py and makeqrc.py as executables, they have python bang path.
Use resources makeqrc and compile code, reducing code redundancy.

An empty __init__.py file was added so functions can be imported.
Use len() instead of a counter.
Use unix eol in generated ressource file.
Create a function to parse amazon urls and reduce code redundancy.

A test for amazon url parsing was added.
Merge pull request #136 from zas/resources_tools

Improve resources tools
Merge pull request #138 from zas/parse_amazon_url

Create a function to parse amazon urls and reduce code redundancy.
Merge remote-tracking branch 'upstream/master' into status_icons