v1.20

Mostly fixes.

• Fixed InputInt() InputFloat() label not declaring their width, breaking usage of SameLine().
• Fixed hovering of combo boxes that extend beyond the parent window limits.
• Fixed text input of Unicode character in the 128-255 range.
• Fixed clipboard pasting into an InputText box not filtering the characters according to contents semantic.
• Dragging outside area of a widget while it is active doesn't trigger hover on other widgets.
• Activating widget bring parent window to front if not already.
• Checkbox and Radio buttons activate on click-release to be consistent with other widgets and most UI.
• InputText() nows consume input characters immediately so they cannot be reused if ImGui::Update is called again with a call to ImGui::Render(). (fixes #105)
• Examples: Console: added support for History callbacks + some cleanup.
• Various small optimisations.
• Cleanup and other fixes.