IsWindowHovered(): Changed default behavior to now return false is a widget from another window is active + Added support for ImGuiHoveredFlags_AllowWhenBlockedByActiveItem. (relate to drag'n drop idoms: #143)

IsItemHovered(), IsWindowHovered(): added flags to enable various and more specific behavior. Will enable improvements for popups/context menus and drag'n drop. (relate ~#439, #1013, #143, #925) ...

The legacy confusing IsItemRectHovered(), IsWindowRectHovered() can be completely removed now.
Changed IsWindowHovered() behavior with default parameter: it now return false is the window is blocked by a popup.
Demo: Added tests for those two functions.

Demos: Tweaks of popups/context/menus section.

CollapsingHeader(bool*) variant: fixed for IsItemHovered() to work properly in the nav branch.Basically the close button now has to use ItemAdd() to be navable into, which overwrite the IsItemHovered data. (#600, #787)

CollapsingHeader(bool*) variant: fixed for IsItemHovered() to work properly in the nav branch.Basically the close button now has to use ItemAdd() to be navable into, which overwrite the IsItemHovered data. (#600, #787)

Merge branch 'master' into navigation ...

# Conflicts:
#	imgui_demo.cpp

Begin: Work toward obsoleting the 5-arguments Begin() overload. Removed bg_alpha from internal BeginEx(). (3)

BeginPopupContextItem() now supports a NULL string identifier and uses the last item ID if available. For interactive items (that have an ID) this works! For non interactive items we assert.

Merge branch 'master' into navigation

Rnamed AlignFirstTextHeightToWidgets() to AlignTextToFramePadding(). Kept inline redirection function (will obsolete).

TreeNode: Added ImGuiTreeNodeFlags_FramePadding flag

Added ActivateItem(), GetItemID() functions.

Demo: better demo for SetKeyboardFocusHere()

Nav: Allow to collapse tree nodes with NavLeft and open them with NavRight (#787, #1079)

Nav: Fixed SetItemDefaultFocus from stealing default focus when we are initializing default focus for a menu bar layer (#787)

Demo: Added an extra test related to baseline and fixed an id collision.

Demo: Added an extra test related to baseline and fixed an id collision.

Merge branch 'master' into navigation ...

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

Fixed IsItemHovered() - part of the processing has to be done in ItemAdd() because the widget may alter clipping rectangle temporarily.

Merge branch 'master' into navigation

ItemAdd(), not performing computation for IsItemRectHovered() which does them itself, allowing us in the next commit to optimize ItemAdd() and make its logic more consistent with IsHovered().

Merge branch 'master' into navigation

ImFont: Renamed (supposedly internal) fields (e.g. XAdvance to AdvanceX). Custom text renderers might be affected if they didn't use the GetCharAdvance() helper function.

ImFont: Renamed ImFont::Glyph to ImFontGlyph (for consistency and so ImFontAtlas types can use it without ordering half of the file). Left a redirection type.

Merge branch 'master' into navigation

Demo: Fixed overlay demo keeps resizing (in case, e.g.: font changes)

SetNextWindowPos: added a ImVec2 pivot parameter for positioning a given a center, bottom-right position, etc. As a generalization of SetNextWindowPosCenter() which is now obsolete. This will be useful for combo-like popups as well. ...

Demo: Simple-overlay window uses the SetWindowPos pivot to select a corner to position itself at.

Added io.WantMoveMouse flags from Nav branch so Examples/Binding can already implement it. (#787)

Merge branch 'master' into navigation

Merge branch 'master' into styles