Refactoring read/write mechanics.

Refactoring and comprehensively reviewing read/write mechanics in order to be more stable/logical/readable. Wrote and tested BufferSegments to manage the entry's content, as well as to efficiently handle applying updates. Have not yet integrated BufferSegments into the general functionality, nor have I tested any of the other changes.
BufferSegments still untested. Split files.
Theo. fixed split_path resolution. Still untested.
Further bug fixes. Still can't read file.
Major debugging and progress.

Formatting conformance fixes. Finished debugging of grand-split operation. Debugged all of the new OpenedFile refactorings and BufferSegments. Read now works for both small and large files. Still need to debug writes.
Integrated BufferSegments.
File read and write debugged.

Still need to verify write for larger files. Also need to investigate "__init__() takes at most 2 positional arguments" message that I see in the log. We now log to an app-specific file (we got sick of the newlines being folded with Syslog).