Add loggers for Vim and IDE

Added 3 loggers:
- Vim Logger, which just appends lines to the given log file
- IDE logger, which just writes to $stderr
- Fake logger, which doesn't do anything

We use Fake logger when debug mode is disabled, or for tests.
Merge pull request #9 from astashov/add-loggers

Add loggers for Vim and IDE
Bump version to 0.2.0
Initial attempt to provide multi-process debug.
Some code copied from ruby-debug-ide.
Unused --cport arg removed
Merge changes