Merge branch 'master' of https://github.com/ggtucker/imgui into ggtucker-master ...

# Conflicts:
#	imgui.cpp
#	imgui.h

ImFontAtlas::AddFontDefault: Made it possible to override size (even if it isn't really recommended)

ImFontAtlas: Re-arranging code to simplify implementation of imgui_freetype. (#618)

ImFontAtlas: Re-arranging code to simplify implementation of imgui_freetype. (#618)

ImFontAtlas; Re-arranging code to simplify implementation of imgui_freetype (#618)

ImFontAtlas: Draft of an api to submit custom rectangle (not exposed). Atlas default texture chunk using it. (WIP: we are still storing mouse UV outside in GImGui)

ImFontAtlas: Some shallow renaming + added an assert for clarification

ImFontAtlas: Shuffling some code inside Build() to make upcoming diffs less confusing (nb: we might break compat with forks of Build() like #618)

Whitespace fix to previous

Make font atlas packing padding configurable

ImFont::CalcWordWrapPositionA: minor optimization

Revert d2c219d #826 + tidying up ImFont::RenderChar()

Merge pull request #826 from swetland/patch ...

ImFont: add RenderGlyph() to allow rendering of individual glyphs post-query

PathArcToFast: Minor renaming for clarification. Comments.

Added ImFontAtlas::GlyphRangesBuilder helper + doc

Use ~IM_COL32_A_MASK instead of IM_COL32(255,255,255,0)

imDrawList::PathRect() uses ImGuiCorner_ enums. Should fully promote this to imgui.h at some point.

ImDrawList::PrimReserve() minor renaming of locals to make things clearer

Comments. Removed sort-of duplicate access to GImGui->Font in ImDrawList::AddText() so it's only in one place.

Version 1.51 WIP tag

Fixed comment (#1178)

Version 1.50

ImFontConfig: Removed MergeGlyphCenterV in favor of a more multipurpose ImFontConfig::GlyphOffset. (Breaking change)

ImFontConfig: Added GlyphOffset to explicitely offset glyphs at font build time, useful for merged fonts. May remove MergeGlyphCenterV soon.

Fixed computation of ImFont::MetricsTotalSurface not taking oversampling into account

Renamed ImDrawList::PathFill() to ImDrawList::PathFillConvex() for clarity. (breaking API)

ImDrawList::AddImage* renamed uv_ parameters to be more consistent. Fix AddImageQuad to use IM_COL32_A_MASK (#1009)

Add ImDrawList::AddImageQuad ...

Adds a function
  AddImageQuad(user_texture_id, a, b, c, d, uva, uvb, uvc, uvd, col)
that shows a texture on a full quad. This allows showing arbitrary
rotations of a texture.

Added assert/comment about using MergeMode (#1100)

ImFont: Store the texture surface used to get an idea of how costly each font is.