Add support for -s device_serial option

It will pass the '-s serial_number' option to adb to select
which device to monitor
Code style tweaks.
UTF-8 decode and trim each line.

Closes #18.
Add 'F' level to log levels.
Remove craziness around native tag bug line regex.
Fix bug line matching.
Merge pull request #26 from xperimental/fix-bugline

Fix bug line matching.
Added arguments for selecting device/emulator analogue to adb.
Merge pull request #27 from xperimental/simple-select

Add arguments for selecting device/emulator analogue to adb
Better regex
Fix trim changes
Merge pull request #28 from dmarcato/master

Better regex for line detection
merged with upstream changes.
use upstream content.