Finish exercise 43 for online statistics.
Reimplement mean and stddev as macros instead of functions.
Redid statistics module in python and added tests too.
Ignore .pyc files from previous comit.
Ringbuffer data structure from ex44 implemented.
Start to ringbuffer unit tests from ex44.

TODO: Finish testing read_write and destroy.
Add performance profiling to string_algos_tests via stats data structure.
Implement file_stats.c to read from file. Not done with bstrlib.
Implement simple TCP/IP client for exercise 45. Makefile also adjusted to compile properly.