ImFont::RenderText() faster handling of rendering above clipping rect (useful for #200)

InputText() clear selection when using undo/redo (#200)

InputText() tidying up (#200)

InputTextMultiline() preserve activeid/cursor/selection when using scrollbar + tidying up (#200)

Speeding up some wchar<>UTF8 functions and some specialization for Ascii. (testing 500 KB text for #200)

Cleanup

InputTextMultiline() can clip + BeginChildFrame() returns bool. (#200)

Demo for InputTextMultiline() (#200)

Demo for InputTextMultiline() (#200)

InputText(): shallow tweaks (#200)

InputTextMultiline() fixes, vertical scrolling, optimizations (#200) ...

Using a child window for multi-line text.

Increased key repeat rate for non-character input key repeat. ...

Dodgy - we should have a match here for character input and
non-character input (e.g. holding 'a' vs holding 'backspace' should be
same rate), but for the earlier we don't have the info?

InputText: doesn't reset scrolling when active text input becomes bigger than its content. (#200) ...

Mostly because it's expensive.

InputTextMultiline(): vertical scrolling wip, selection rendering fix (#200)

InputTextMultiline(): multi-line selection draw fix (#200)

InputTextMultiline(): multi-line selection draw fix (#200)

InputText() fixing cancel (#200)

InputText() lifted 1024 characters limit (#200) ...

Bit messy & not happy with using ImVector<char>

InputText() fixed multi-line selection clipping. (#200)

InputTextMultiline() tabbing to a multi-line edit doesn't select all (unless ImGuiInputTextFlags_AutoSelectAll is set), somehow arbitrary (# ...

Seems reasonable

InputText: multi-line selection, better scrolling, cleaning up (#200) ...

Not horizontally scrolling on char boundaries anymore

ImFont::RenderText() additional early out (typically performed at TextUnformatted() level for large chunks but this is also useful) (#200)

Merge remote-tracking branch 'origin' into 2015-06-multiline_textedit ...

Conflicts:
	imgui.h

Text rendering can be finely clipped cpu-side on top and left axises (for #200)

Merge remote-tracking branch 'origin' into 2015-06-multiline_textedit ...

Conflicts:
	imgui.cpp

Moved InputFloat() InputInt() below InputText() and not in the middle of internal bits

InputTextMultiline() WIP - still gazillion problems with selection visualisation & scrolling

ImFont: added GetCharAdvance() helper. Exposed font Ascent and font Descent.

ImageButton() changed default bg_col parameter from (0,0,0,1) black to (0,0,0,0) tranparent + drawing frame even when no padding (#243)

Selectable() changed prototype moved flags before size. size override should rarely have been used! sorry. #125