API changes and normalization

Changes:

* Make the API less awful with descriptive return values from `pagein` and `pageout`
* Make the API less awful with descriptive page state information in the input to `pageit`
* Whitespace and formatting normalization
* Merge READMEs

I did my best to make the commits granular enough that the diffs are comprehensible: no ball-of-mud commits here, with the possible exception of the whitespace and formatting normalization commit. The API changes are documented in the header file, but the writeup has not been changed. I thought it best to make the changes to the writeup once the API changes have been reviewed and merged.