[crertel]

Adds Mat44.make_reflect/2 and make_shear_x/2, make_shear_y/2, and make_shear_z/2 for 3D affine transformations. All constructors preserve the fourth, homogeneous coordinate and use the library's row-vector convention.

Reflection accepts a nonzero plane normal and the equation constant in nx*x + ny*y + nz*z = offset. The normal need not have unit length; a zero normal raises ArithmeticError. Offset reflections translate points while directions receive only the linear reflection. Each shear changes its named axis using the other two spatial coordinates.

Module and transform docs explain points (w = 1), directions (w = 0), and the absence of perspective division in transform_point/2. All constructors retain float typespecs and explicit float clauses with numeric fallbacks.

Validation: 552 tests and 3 doctests pass with 100% line coverage after rebasing onto master with #62, #63, and #64 merged. Tests cover coordinate and oblique planes (including both 0 and 0.0 offsets), normal/offset scaling, reflection invariants, homogeneous coordinates, every shear axis, inverses, composition order, translation, and fractional/mixed inputs. For zero offsets, X, Y, Z, and oblique normals all exercise integer, float, and mixed inputs, with checks for fixed points, no translation, expected point/direction results, and preservation of the homogeneous coordinate. Formatting, compilation with warnings as errors, and documentation generation pass.

Part of #44.

[coveralls]

coverage: 100.0%. remained the same — 44-mat44-transforms into master

[coveralls]

coverage: 100.0%. remained the same — 44-mat44-transforms into master