Prefix exported symbols with "cmaes"

This is a redo of #9. 

In #9, @sherm1 mentioned: 

```
I think there were a couple more externs at the end of cmaes.c that didn't get fixed: ERRORMESSAGE() and szCat(). Maybe Niko can check whether these or some other routines were intended to be static in which case they wouldn't need the cmaes prefix.
```

It does seem that these symbols were meant to be static, since they are declared as static. I have marked them as static at their definition now too.

To make these changes, I effectively ran the following shell script:

```
perl -p -i -e 's/boundary_transformation(?!\.)/cmaes_boundary_transformation/g' c-cma-es/* c-cma-es/src/*                                                                        perl -p -i -e 's/readpara(?!\.)/cmaes_readpara/g' c-cma-es/* c-cma-es/src/*                                                                                                      
perl -p -i -e 's/timings(?!\.)/cmaes_timings/g' c-cma-es/* c-cma-es/src/*                                                                                                        
perl -p -i -e 's/random(?!\.)/cmaes_random/g' c-cma-es/* c-cma-es/src/*
```

and made some manual tweaks after that to comments, etc.

I tested that the code still compiles (by running the compile script), and that the resulting executables all run. I did not check the results, though.