[NSWI004] Missing try* tests, deadline extension

[Vojtech Horky]

Hello,

I forgot to add tests for the try-variants of the synchronization 
primitives for assignment #4. I have already added them to the upstream 
repository (commit e0a04a6).

Because I understand that some of you might have forgotten about the 
try* functions when no tests warned you about missing implementation, we 
have extended the deadline for #4 to Friday 13th.

Next assignment will be announced later today.

Thank you,
- VH