Applying Placemark.imageRotation to non-squre images stretch them

[EMaksymenko]

Description

Applying Placemark.imageRotation to non-squre images stretch them.

Steps to Reproduce

Specify any non-square image as source of Placemark and set any non-zero imageRotation.

Expected behavior: Image should save its proportions

Actual behavior: Image stretch to original width and height

Reproduces how often: always

Additional info

JS code base has the same issue. Java code base use GL2 instead of Matrix for rotation and has no issue.
WorldWindEarth/worldwindjs#63