Blueprint history will now leave the user in the graphs that were open when the Blueprint was last closed and will provide history to go back up the breadcrumbs to the top-most graph instead.

Added a QuickNavigateCurrentDocument option, basically prevents the history data from being saved to avoid capturing of bad placement of graphs during this process.

#codereview Nick.Whiting

[CL 2222334 by Michael Schoell in Main branch]
Updated README.md
Updated .gitignore
Support for modular builds (cross and native).

- Parts of PR #242 (with changes).

#codereview Josh.Adams

[CL 2222405 by Dmitry Rekman in Main branch]
#UE4

    not all ES2 implemenations support npot textures with a wrap mode different form clamp to edge.

#codereview rolando.caloca

[CL 2222440 by Ankit Khare in Main branch]
#UE4 - changes to voip delegate processing
- prevent some possible crashes
- fix LIVE implementation (NULL can't call ToSharedRef)
#codereview ryan.gerleve

[CL 2222457 by Josh Markiewicz in Main branch]
Fix incorrect PIEInstance getting set on multi-player PIE world context

[CL 2222462 by Marc Audy in Main branch]
UMG - Add design time property updates an blueprint support for the Throbber and CircularThrobber.

[CL 2222494 by Frank Fella in Main branch]
Deleting unused variables is now an undoable action.

Added a transaction when the action occurs.

#ttp 340635 - BP: hitting undo after using  'delete unused variables'  restores 1 variable less than the variables deleted

[CL 2222507 by Michael Schoell in Main branch]
Actually ES2 does support MSAA resolve on PC emulation.

[CL 2222513 by Timothy Lottes in Main branch]
Improved RMB handling in SNodePanel for Magic Mouse and trackpad

[CL 2222518 by Michael Trepka in Main branch]
Fix DOF lock getting garbage collected on skeletal mesh

[CL 2222562 by Ori Cohen in Main branch]
Linux toolchain: replace slashes properly (also account for escaped ones).

[CL 2222564 by Dmitry Rekman in Main branch]
Minor fix (ignoring function arg, caught by CIS).

#codereview Frank.Fella

[CL 2222593 by Dmitry Rekman in Main branch]
Fix CIS (missing forward declaration).

#codereview Gareth.Martin

[CL 2222594 by Dmitry Rekman in Main branch]
Fix for thumbnail rendering producing black or incorrect thumbnails

#codereview Bob.Tellez

[CL 2222597 by Martin Wilson in Main branch]
Functions and macros now will display with their category in the My Blueprint panel.

Also mass delete and changing categories allowed to functions, macros, and delegates.

#ttp 341290 - BP:  Add support for categories for functions in the My Blueprints tab

[CL 2222608 by Michael Schoell in Main branch]
A bit more CIS fixing.

[CL 2222621 by Dmitry Rekman in Main branch]
UE4 - Metal format fix
#codereview Josh.Adams

[CL 2222633 by Rolando Caloca in Main branch]
Automation:  Milestone1 fixes

Asset Creation and Duplication test
 -Enabled Behavior trees while the test is running
 -Skipped assets that require a skeleton if we didn't find one to use
 -Skipped creating a data asset if GameplayAbilitySet is not found

[CL 2222639 by kevin hamilton in Main branch]