Minor fix to index check in mditab_get_item
Merge pull request #1 from ArmstrongJ/mditab_fix

Minor fix to index check in mditab_get_item
[README] Fix typos and minor outdated details.
[README] Fix typo.
[TREELIST] Fix typo in doc.
[MDITAB] Change scroll logic.

The scrolling logic is now pixel-based instead of itme-index-based.
This will allow to implement scrolling animation.
[MDITAB] Add message MC_MTM_GETITEMRECT.
[MDITAB] Make new layout of items keep scrolling position in allowrd range.
[MDITAB] mditab_layout() updates hot item.
[misc.h] SelectClipRgn() expects device coordinates.
[MDITAB] Add style MC_MTS_ANIMATE to animate some operations.

 * When set, animate scrolling and item layout changes.
 * Update docs.
 * Make example use the style.
[THEME] Make the module public.

 * Added new public header mctrl/theme.h
 * Reworked src/theme.c
 * Updated all callsites (most controls).
[THEME] Be more verbose about current theming usage.
[THEME] Fix typos.
[THEME] Do not attempt to GetProcAddress of SetWindowThemeNonClientAttributes().

It is not exported from UXTHEME.DLL, it is only inlined function in <uxtheme.h>.
[MDITAB] Make public mCtrl/theme.h compatible with older _WIN32_WINNT.

<uxtheme.h> defines some types (and functoins) only if _WIN32_WINNT
is set to 0x0600. We follow these in our header as otherwise if app.
does not define it (or if it uses smaller value), has compile time
errors due to some undefined types.
[THEME] Workaround for unfunctional IsAppThemed() and IsCompositionActive()...

... if no window was ever created in the process.
[THEME] Export mcTheme_Initialize() and mcTheme_Terminate().
[MAKEFILE] MCTRL.DLL depends also on mCtrl.def.
[THEME] Make UXTHEME's function poitners global.