ASSignpost: Add support for the os_signpost API, fixes (TextureGroup#… …1501) * ASSignpost: Add support for the os_signpost API - Removes support for colored intervals. These weren't really useful and they aren't part of the signpost api. - Fixes an issue with range controller interval logging. - Adds an interval for interface orientation changes. * Rename * Support Xcode 9 * Commentary

Cut version 2.8.1 

Correct attributes lookup for supplementary elements. (TextureGroup#1318 )

Correct attributes lookup for supplementary elements. (TextureGroup#1318 )

[Updated Snapshots] Don't add extraneous truncation token during kCTL… …ineTruncationMiddle (TextureGroup#1375) * Don't add extraneous truncation token during kCTLineTruncationMiddle * Expand these comments a little. * Update snapshot tests with beautiful correct behavior

Fix duplicate definition of category "YogaDebugging" (TextureGroup#1331) 

Wrap supplementary node blocks to enable resizing them. (TextureGroup… …#1265) * Wrap supplementary node blocks to enable resizing them. Most ASCellNodeBlocks are wrapped by ASCollectionView.mm to add an `interactionDelegate` as well as calling `enterHierarchyState` on the node and setting its transform to a reflection if `inverted` is set on the collectionView. This PR adds this behavior to supplementary nodes as well. * Simplify code / block will never be nil

Move AS_TEXT_ALERT_UNIMPLEMENTED_FEATURE into ASTextNodeCommon (Textu… …reGroup#1191)