WIP: Jekyll File System Manager

In order to achieve peak security, it is very important to have all access to the file system jailed to a certain directory. This prevents things like symlinks or maliciously-named files from accessing files outside the directory jail.

- [ ] Create File System manager of some sort
- [ ] All calls to the FS must be conducted via this manager
- [ ] Convert `Page` into a 
- [ ] Add tests
- [ ] Gemify