0.1: Initial release

Help message:
```
usage: sleepcount.py [-h] [-c] [time [time ...]]

positional arguments:
  time             time either could be defined as:
                   1) integer number of seconds or may be 's' for seconds (the default),
                   'm' for minutes, 'h' for hours or 'd' for days;
                   2) target time, '%H:%M' or '%H:%M:%S'.

optional arguments:
  -h, --help       show this help message and exit
  -c, --countdown  show interactive countdown
```