Added comments regarding the choice to use stdint and remarked on the exceptional cases in isPrime().
Completed problem #4. My initial attempt at optimizing the math operations failed, so I will revisit this soon based on the feedback from 004_overview.pdf
Merge branch 'master' of https://github.com/xcjs/project-euler

Merging master down since adjusting some typos found in README.md online and completing problem number 4 in my local workspace.