New constructors and functions

Completed this commit:
- Added constructors that take the newly typedef'd FileIterators
- Added more templated removeIf functions
- Fixed documentation in the equality testing operators
- Fixed the [] operators to make them more consistent with each other
To be completed:
- Add further templatization for removeIf functions
- Add more convenience functions
- Optimizations
- Fully test each function to make sure they all work properly
- Finalize the behavior of each function so that all the functions
behave in a consistent and intuitive manner
- Document each function more fully to explain in detail why and how it
does what it does