Fork of Simple X Image Viewer

This is a personal project, started mainly to address the first point in the next section. Afterwards some more made their way through.

It was created was before Nsxiv, which today is very likely your best option since it's actively mantained and improved by a team.

Changes

If a single image argument is given, the image is displayed as expected, but all other images in the directory are also loaded for navigation (#352).
- If more than one argument is given, then only the specified files and directories are loaded, as in mainstream Sxiv.
No file will ever be loaded twice.
Additional configurable options (via X-resources):
- Marks are more conspicuous, a red rectangle around the image.
- Status bar colors.
- External key handler can be invoked in a single key press.
- Square thumbnails.
- Window title consists of a prefix and a suffix. The prefix is a fixed string and the suffix is one of
```
0  Basename of file
1  Basename of directory
2  Full path to file
3  Full path to directory
4  Empty string
```
  The default window title is "sxiv - {file basename}".
- The full-screen background can be different.
- Hide bar (alternative to -b command line option).
Escape key can be mapped in config.h.

$ make
# make install