updated shader to use specular map and tangent normals for shading/lighting

updated model functions to load tangent normals, and return 4 dimensional vector

fixed Vec4f operators

added reading of specular multiplier

added colored texture rendering. first draft of parameters used to render colored textures

refactored shader to use normal mapping for across uv coordinates

added routines for obtaining normal from normal map using uv coordinates

refactored model to store faces that have vertex, normal, and texture index mappings. loaded in texture image and stored uv coordinates

added reading normal vectors from .obj files, added curved geometry using barycentric interpolation of normal vectors. added TODO for potential future work

corrected computation of normal, light, reflection, and camera unit vectors by removing subtraction of position

first draft of Phong reflection model

refactored main to move transformation matrices into our_gl files, refactored render pipeline to more closely reflect opengl

fixed refactoring to use transformation matrices on vertices. refactored functions to accept templated types. fixed bug in depth buffer and converting to integer

created loop to transform vertices using new matrices. TODO: remove transformVertices, as viewport transformation done already

finished routines to generate transformation matrices for viewport, perspective, and looking at model from different camera positions