Updated Makefile to include more specific globs
Update test and assertion count
Removed `TextOM.Node#type` from docs
Removed `Node#type` from IDL
Added `TextOM.Parent#split` to IDL
Added hierarchy definitions to IDL
Api changes; bug fixes.

- Better comments: More info, better whitespace. Less extraneous comments;
- Better errors. More usefull, and messages are more in line with ECMAScript;
- Better line endings (no line exceeds 80 characters);
- Fixed a leaking variable in `_walkForwards` and `_walkBackwards`;
- Removed `Node#type`;
- Added `Parent#split`, splitting a parent into two;
- Removed `WhiteSpaceNode#hierarchy`, as these nodes can be inserted anywhere;
- `Range#setStart()` and `Range#setEnd()` now accept unattached nodes;
- `Range#setStart()` and `Range#setEnd()` now accept `NaN` as an offset, and convert it to `0`;
- `Range#setStart()` and `Range#setEnd()` now accept `Infinity` as an offset;

- Added more tests: `hierarchy` attributes, `HierarchyError`s;
- Better `assert.throws` tests, now including validating the error message;
- Fixed some casing/naming errors.