Describe radix-k algorithm.

ietAddTile raises ICET_INVALID_VALUE if you try to create a tile with no
pixels.

icetFindRankInGroup, icetFindMyRankInGroup

The following state variables are not set with sequential strategy:
ICET_ALL_CONTAINED_TILES_MASKS, ICET_TILE_CONTRIB_COUNTS, and
ICET_TOTAL_IMAGE_COUNT.

Suggest using sequential strategy for single tile (because it skips some
allgathers).

icetCommBarrier

icetImageAssignBuffer, icetSingleImageAssignBuffer

icetWaitany returns index to finished request - different than MPI.

icetCommGather, icetCommGatherV

ICET_IN_PLACE_COLLECT

ICET_SIZE_TYPE (list of types in implement new strategy -> Communications).

const array for compose_group in single image strategy functions.

icetSingleImageCompose interface change.

icetSingleImageCollect.

General change to single image strategy functions.

ICET_MAGIC_K state variable, CMake variable, and environment variable.

icetCompressedCompressedComposite

icetSparseImageCopyPixels

icetSparseImageSplit

icetSparseImageSplitPartitionNumPixels

icetImageEqual, icetSparseImageEqual

icetDecompressSubImage

icetRenderTransferSparseImages

icetSparseImageNull, icetSparseImageIsNull

icetUnsafeStateGet* now return const

todo: correct background before gather

ICET_INTERLACE_IMAGES

icetSparseImageInterlace

ICET_MAGIC_K environment variable, cmake variable, state variable

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.

ICET_MAX_IMAGE_SPLIT environment variable, cmake variable, state variable

All the matrix math helpers icetMatrix* in IceTDevMatrix.h

Const versions of icetImageGetColor* and icetImageGetDepth* functions.

Added Alltoall to communicator.  (Search for Allgather for places to add in
documentation.)

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.
