We may need to drop the $prefix to the udev rules from configure.ac

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

When light is installed in the non-SUID root mode it cannot write to
/etc/light anymore, so we set up a ~/.cache/light instead.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

This patch adds support for installing the 90-backlight.rules to gain
privileges to the kernel sysfs files.  By default the classic SUID root
mode is used and the rules file is not installed.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

- Use version from configure script
- Simplify usage text for accessibility, only one command at a time
- Simplify terminology, we have commands and options to commands

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Most users want to see the examples as early as possible, so we place
them directly after the new (simplified) introduction.  The examples
have been rewritten to separate commands from options and grouping
the command with its value, where applicable.

The rest of the document has just been auto-filled to fit to < 72
columns and sections now use === and ---- for headings to make the
README more accessible from a terminal.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

Also add more examples