Fix a bug in ImGuiTextFilter and extend it to be more customizable

[kudaba]

Context:
Depending on the context I like to use different filtering modes. This lets me tweak the behavior without having to completely write a whole new system each time.

I made sure to preserve the current behavior and performance.

Changes:

• Fixed negative matches not working when located after a positive matches. Optimized by keeping all negative matches at the front of the filter list.
• Add the following customization options:
  • Custom split character, default is still ','
  • Minimum word match length can be used to keep the search more stable for the first couple characters of input
  • Match mode can be switch from Or (any pass causes a success) to And (all positive filters must match).
• Add a utility to allow applying a single filter to multiple fields.

Multi field filter usage:

ImGuiTextFilterMatch match(myFilter);
match.PassFilter(item.Name);
match.PassFilter(item.Error.ToString());
match.PassFilter(item.Message);

if (match)
{
	...
}

[ocornut]

Why closing and deleting this?

[kudaba]

I was updating/cleaning up old prs, must have mis-clicked on this one, it's still alive and well.

[phisko]

Created kudaba#1 to extend this by exposing the new customization options to users