fixed a mistake with the header includes for the library and the tests
* fixed some typos in testreadln
* reimplemented testflush
* testsuite/arduserial/testinit.c: includes the test header now
* testsuite/arduserial/testreadln.c: added some debugging output, renamed buffer variable for ser_read
* testsuite/arduserial/testflush.c: fixed a bug so that the test works correctly
deleted a line in Changelog that was not needed
revision increased to 3 and version of package to 1.9