Added documentation description of:

- icetUnsafeStateGet now returns const.
- new ICET_COLLECT_TIME timing metric.
- ICET_COLLECT_IMAGES option.
- ICET_VALID_PIXELS_* state variables.
- Matrix helper functions.
- Input array for icetSendRecvLargeMessages became const.
- Background correction in strategies.

Changes.txt

-icetUnsafeStateGet* now return const
-
-ICET_COLLECT_TIME: The fraction of ICET_COMPOSITE_TIME spent in collecting
-image fragments to display process.
-
-ICET_COLLECT_IMAGES: When this option is on (the default) images partitions
-are always collected to display processes (the current behavior).  When
-turned off, the strategy has the option of leaving images partitioned
-amongst processes.  Each process containing part of a tile's image will
-return the entire buffer from icetDrawFrame in an IceTImage object.
-However, only certain pixels will be valid.  The state variables
-ICET_VALID_PIXELS_TILE, ICET_VALID_PIXELS_OFFSET, and ICET_VALID_PIXELS_NUM
-give which tile the pixels belong to and what range of pixels are valid.
-
-ICET_VALID_PIXELS_TILE: Gives the tile for which the last image returned
-from icetDrawFrame contains pixels.  Each process has its own value.  If
-the last call to icetDrawFrame did not return pixels for the local process,
-this variable is set to -1.  This state variable is only useful when
-ICET_COLLECT_IMAGES is off.  If on, it can be assumed that all display
-processes have valid pixels for their respective display tiles, and all
-other processes have no pixel data.  Strategies taking advantage of turning
-off ICET_COLLECT_IMAGES should set this.
-
-ICET_VALID_PIXELS_OFFSET, ICET_VALID_PIXELS_NUM: Gives the range of valid
-pixels for the last image returned from icetDrawFrame.  Given the arrays of
-pixels returned with the icetImageGetColor and icetImageGetDepth functions,
-the valid pixels start at the pixel indexed by ICET_VALID_PIXELS_OFFSET and
-continue for ICET_VALID_PIXELS_NUM.  The tile to which these pixels belong
-are captured in the ICET_VALID_PIXELS_TILE state variable.  If the last
-call to icetDrawFrame did not return pixels for the local process,
-ICET_VALID_PIXELS_NUM is set to 0.  This state variable is only useful when
-ICET_COLLECT_IMAGES is off.  If on, it can be assumed that all display
-processes contain all pixels in the image (ICET_VALID_PIXELS_OFFSET is 0
-and ICET_VALID_PIXELS_NUM is the number of pixels in the image), and all
-other processes have no pixel data.  Strategies taking advantage of turning
-off ICET_COLLECT_IMAGES should set this.
-
-All the matrix math helpers icetMatrix* in IceTDevMatrix.h
-
-Const versions of icetImageGetColor* and icetImageGetDepth* functions.
-
-icetSendRecvLargeMessages takes const array for messageDestinations.
-
-ICET_CORRECT_COLORED_BACKGROUND is now the responsibility of the strategy,
-not done automatically.  icetSingleImageCollect does it for you, though.
-
-Added internal state variables ICET_NEED_BACKGROUND_CORRECTION,
-ICET_TRUE_BACKGROUND_COLOR, and ICET_TRUE_BACKGROUND_COLOR_WORD.
-
-icetImageCorrectBackground, icetClearImageTrueBackground,
-icetDecompressImageCorrectBackground, and
-icetDecompressSubImageCorrectBackground functions.
-
 Future work: update scalability tests done.
 Future work: multithreaded.
 Future work: lean memory.
 Future work: big image strategy.
+Future work: expose matrix functions?