libigl_Martin/include/igl/viewer/TODOs.txt

- `align_and_center_object` continues to zoom out on repeated calls
- data.lines, data.points should not concatenate colors with coordinates
- snap to canonical recenters origin but trackball does not
- rewrite in libigl style
- separate various class into their own .h/.cpp pairs
- remove use of double underscores (http://stackoverflow.com/a/224420/148668)
- document inputs and outputs to all functions
- document all member fields
- document all classes
- light direction is backwards
- remove global variables (not threadsafe)
- encapsulate (in igl namespace) and move static/global functions, use lambdas?
- preface macros with "IGL_"
- trackball mouseup captured by tweakbar
- zoom with pan rather than scaling
- refresh draw while resizing
- use constructor initializer list rather than complicated constructor
+ snap to canonical view key shortcut is not working
+ resize TwBar with window
+ trackball should be able to drag over TwBar
+ don't zoom on horizontal scale
+ remove global `using namespace std`
+ remove `#define IGL_HEADER_ONLY`
+ guard `#undef max`
+ fix all -Wsign-compare
+ missing `#include <iostream>`
+ missing `#include <fstream>`
+ fix all -Wunused-but-set-variable
+ makefile for libiglviewer.a
+ Viewer.h should include Viewer.cpp
+ depth test for overlays cannot be disabled