----- Contents-<ARCH>.gz -----
    /bin/afio                                      /main/afio/
    /usr/share/icons/exaile.png                    /universe/exaile/
    /usr/share/icons/hicolor/64x64x/exaile.png     /universe/exaile/

----- Search Directories -----
SEARCH_DIRS = {"usr/share/icons/hicolor/64x64",
               "usr/share/icons/hicolor/48x48",
                .............................
               "usr/share"}


SIMPLIFIED PROCESS

1. IconFinder instantiation.
2. For each SEARCH_DIR, create a cache file containing only Contents.gz
   lines beginning with SEARCH_DIR.
3. Load maximum cache data possible into memory.
4. [Desktop data extraction begins]
5a. Desktop data extraction calls for icon "foo.png"
6a. IconFinder searches all cache files (or cache memory, if loaded) in
    order of SEARCH_DIRS. Returns first result.
5b. Desktop data extraction calls for icon "/abs/path/to/foo.png"
6b. IconFinder binary searches Contents.gz (or cache memory, if loaded)
    for that exact path. Returns any result.

BENEFITS

a) Complete. Any icon in /usr/share will be found, full stop.
b) Fast. Manual deb searches (the current approach) require many
   random disk accesses. In this approach, most icons will be located
   through caches in RAM.

DRAWBACKS

a) Will require rewriting some unit tests
b) More memory use for fast searches