Fix cilineendings_unittest +style issues

Wrapped lines in cilineendings_unittest.cpp to 80 columns Renamed test file
with capital 'I' in filename, so it is lower cased. Make use of helper
functions for error checks where possible Expect rather than assert where
possible Safety checks to prevent buffer overflows/out of bounds access

Code corrected so that 'self->column' is reset to '1' each time 
webvtt_proc_cueline is called