Updated Changes and bumped version to 8.0.0a19.

Author: johnhaddon

Changes

@@ -1,3 +1,40 @@
+# 8.0.0-a19
+
+#### IECore
+
+- Removed incorrect assertions from StreamIndexedIO - they were causing crashes in debug builds.
+- ComputationCache is more robust in situations where a call to get() yields a different object than was passed to set().
+
+#### IECoreHoudini
+
+- GEO_CortexPrimitives are now correctly copied and transformed during ObjectMerges.
+- TagFilter now prevents unnecessary expansion of SceneCache nodes. In SubNetwork/AllDescendants mode, the tagFilter is used to prevent expansion into branches of the hierarchy that were not requested. For a heavy asset, filtering by a "Proxy" tag was expanding in 25 seconds and creating 22000 nodes. It is now expanding in 3 seconds and creating 3000 nodes.
+- SceneCache Xform and Geo nodes now have a tagFilter, and pass it through to matching children during expansion and push. Xfrom still uses it to limit expansion and control visibility. Geo just passes it on to the SOP, which uses it to limit objects loaded.
+- Promoted shapeFilter to all SceneCache nodes. SceneCache Xform and Geo just pass it through to the SOP, as with the attributeFilter.
+- Added support for reading and writing tags in SceneCaches.
+- Optimised SceneCache OBJ expansion time. On a heavy asset, this reduces expansion time from 442.3s (7.38m) to 17.12s.
+- Fixed time offset issues caused by Houdini time 0 being at frame 1, whereas it is at frame 0 in Maya, and in SceneInterfaces.
+
+#### IECoreMaya
+
+- Added a flag to the FnSceneShape create so we can directly create a new sceneShape and transform under a given parent. Used when expanding.
+
+#### IECoreNuke
+
+- Fixed a bug in LensDistort that was causing the cache to hold incorrect image data.
+
+#### IECoreGL
+
+- Added ShaderLoader::clear() method, which allows the reloading of GLSL shaders on the fly.
+- Added "gl:primitive:selectable" attribute to Renderer.
+
+#### IECoreRI
+
+- Fixed automatic instancing bug caused by having multiple procedurals in the same RIB file.
+- Added workaround for 3delight 11.0 in IECoreRI::Renderer::worldEnd - this allows rerendering to work again.
+
+####################################################################################################
+
 # 8.0.0-a18 :
 
 #### IECore

SConstruct

@@ -53,7 +53,7 @@ SConsignFile()
 ieCoreMajorVersion=8
 ieCoreMinorVersion=0
 ieCorePatchVersion=0
-ieCoreVersionSuffix="a18"	# used for alpha/beta releases. Example: "a1", "b2", etc.
+ieCoreVersionSuffix="a19"	# used for alpha/beta releases. Example: "a1", "b2", etc.
 
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 # Command line options