Reset GBNclient.c to code given by TA
Worked on client skeleton layout

* Implemented socket creation
client reads file size
added logevent() to client
client: added logic for reading from file
client sends all packets in window
Added timeout calculation
Changed GBNPacket struct send_time and related functions
Added timeout detection

Not fully testing
Added ack timeout logic to client
Fixed one-off error in server

Aded some rules to Makefile too
fixed bug in rbw_get_next_in_window
client now reads full file (~10k)
Various bug fixes