Refactored YUVImage Java class so that it supports both unified YUV image buffers as well as separate YUV image planes;  modified the JNI functions accordingly and added new helper functions to the TurboJPEG C API (tjPlaneWidth(), tjPlaneHeight(), tjPlaneSizeYUV()) to facilitate those modifications;  changed potentially confusing "component width" and "component height" terms to "plane width" and "plane height" and modified variable names in turbojpeg.c to reflect this;  numerous other documentation tweaks

git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1360 632fc199-4ca6-4c93-a231-07263d6284db