Fix ctap_readbdf.m for reading events
Function aims to free CTAP users from having to include Biosig on their path, since it can be awkward on server mounts. Currently works to read bdf data, but fails to read events for some types of files - unclear why.
For a fix, SEE biosig/T200_FileAccess/sopen.m line 1036-1072, which uses only fread.m and bdf2biosig_events.m (latter could be CTAP-embedded)