Exposed CalcTextSize(), GetCursorScreenPos() for more advanced fiddling

Added an assertion

Converted all Tabs to Spaces (git diff -w shows an empty diff)

Todo list

Removed unused parameter in demo window code

Fixed tooltip size (broken earlier today) + added todo items

Removing line from Todo list

Skip most logic is alpha is 0.0, Begin() also return false to allow user to early out

Skip rendering if alpha is 0.0

Undo Begin() return false with Alpha==0.0, misleading at the moment

Initialised window->Accessed in constructor. Begin() return false with Alpha==0.0

Added global Alpha in ImGuiStyle + commented ImGuiStyle fields in .h

memory override attempt #2

minor fixes

Added InputFloat4(), SliderFloat4() helpers.

Invisible child windows gets clipped earlier in the pipeline.

Child window with inverted clip rectangles are marked as collapsed.

Reduce inner window clipping to take account for the extend of CollapsingHeader ...

from arikwestbrook

Allowing the user to call NewFrame() multiple times without calling Render() ...

Note that this is never a good idea. But, allowing it reduce confusion
in the initial stage of setup.

Fix clipping of title bar text.

Minor todo/readme changes

argh, removed redundent defines

removed memory pools, they dont apply well

fixed a typo

merge with upstream

First attempt at memory management

Fixed floating-point precision issue making the right-side value of a plot sometimes wrap to the left-side value.

PlotLines(), PlotHistogram(): added a stride parameter.

Slowed down mouse wheel scrolling speed in combo boxes

TreeNode/CollapsingHeader ignore clicks when CTRL or SHFIT are held + make default button hover brighter