docs: update docs

docs/source/getting_started.rst

@@ -1,5 +1,9 @@
 Getting Started
 ================================
+.. image:: cglm-intro.png
+   :width: 492px 
+   :height: 297px
+   :align: center
 
 **cglm** uses **glm** prefix for all functions e.g. glm_lookat. You can see supported types in common header file:
 

docs/source/index.rst

@@ -9,7 +9,7 @@ Welcome to cglm's documentation!
 **cglm** is optimized 3D math library written in C99 (compatible with C89).
 It is similar to original **glm** library except this is mainly for **C**
 
-This library stores matrices as row-major order but in the future column-major
+This library stores matrices as column-major order but in the future row-major
 is considered to be supported as optional.
 
 Also currently only **float** type is supported for most operations.
@@ -28,7 +28,9 @@ Also currently only **float** type is supported for most operations.
 * euler angles / yaw-pitch-roll to matrix
 * extract euler angles
 * inline or pre-compiled function call
-* more features (todo)
+* frustum (extract view frustum planes, corners...)
+* bounding box (AABB in Frustum (culling), crop, merge...)
+
 
 .. toctree::
    :maxdepth: 2