Using semicolons in optstring of getopt().
Changed indentation in getopt loop.
Periodical DNA writing and reading initial DNA.

New option -S (session mode) that periodically saves most fit image and DNA to file.
Added argument to read initial DNA instead of generating new.
Fixed writing redundant timelapse images.
Fixed proper bytes extraction order (BGRA).

Removed extraction of alpha channel, because alpha is premultiplied.
Merge pull request #2 from naodesu/master

Some bugfixes and DNA reading / writing.