Manually categorize API reference page

Author: abhro

docs/src/api.md

@@ -1,7 +1,47 @@
-# CoordinateTransformations.jl documentation
+# API Reference
 
-## API Reference
+## Transformations
+```@docs
+Transformation
+CoordinateTransformations.ComposedTransformation
+IdentityTransformation
+PerspectiveMap
+inv
+cameramap
+compose
+recenter
+transform_deriv
+transform_deriv_params
+```
+
+## Affine maps
+```@docs
+AbstractAffineMap
+AffineMap
+AffineMap(::Transformation, ::Any)
+AffineMap(::Pair)
+LinearMap
+Translation
+```
+
+## 2D Coordinates
+```@docs
+Polar
+PolarFromCartesian
+CartesianFromPolar
+```
+
+## 3D Coordinates
+```@docs
+Cylindrical
+Spherical
+```
 
-```@autodocs
-Modules = [CoordinateTransformations]
+```@docs
+CartesianFromCylindrical
+CartesianFromSpherical
+CylindricalFromCartesian
+CylindricalFromSpherical
+SphericalFromCartesian
+SphericalFromCylindrical
 ```