Issue #1: terminate child when closing PTY prematurely.

- send a kill signal to the child process if it is still alive;
- fixed a small bug in the closing of the input/output streams;
- added some tests to keep regression on issue #1.
Upgraded to latest JTermios version (embedded in PureJavacomm).
Removed old version of PureJavacomm.
Bumped to version 0.1.0.