Open local logcat file

Asking for possibility to filter existing logcat file (input pipe):
```
cat logcat.txt | python pidcat.py com.developer.strikes
```
or local file
```
./pidcat.py -f logcat.txt com.developer.strikes
```

Start by reading pidcat.py and trace how logcat input is currently received and filtered for the package argument. Exercise the existing command, then verify that both the piped logcat.txt form and the -f logcat.txt form filter the same way for com.developer.strikes.

Written by the indexing model from the issue text.