Initial code
Add testing infrastructure
Add initial gitignore
Finish load functions and add `from_fn` constructor
Fix pnm.tpp testing

Otherwise it creates duplicate definitions
Fix infinite recursions
Add tests for operator()
Make sure row and col are within bounds
Add Histogram
Fix magic checking
Print out tab-separated histogram table
Implement Otsu thresholding

From "Computer Vision", Shapiro and Stockman (2009)
Take the stream in the constructor

This allows the image to be defined as const
Implement PNMImage writing
Remove inexistant make rules
Use const
Break a line
Add a size() method to PNMImage
Cast result to bool
Add initial region-finding implementation