finish the region on deleting it

FangChuang on the Github located this memory leak regarding with windows
creation and deletion.

Github-hook: fix #76
edit: avoid flickering in rtgui_edit_clear_text
move the wintitle from topwin to window
rtgui_server.h: cleanup
window: don't paint the title when active
window: always deactive the window in RTGUI_EVENT_WIN_DEACTIVATE
window: reset the window move state machine on mouse up
textbox: make the flag of textbox an enum
refactor textbox try 2
slider: fix the key handling

Signed-off-by: haitao52198 <413162621@qq.com>
textbox: blink once per second
add widgets/caret and port textbox to it
port edit to caret "widget"
button: fix the border calculation when drawing text

The border is remove above the code so there is no need to remove it
twice.
edit: fix the carect filling when the caret is in more then one page

Thanks amsl for reporting the bug.
edit: fix bug when there is no line under current cursor
listctrl: fix left/right key handling

Thanks haitao for the bug report.
listctrl: preserve the current_item in rtgui_listctrl_set_items
window: record the outer clip

If we don't record the outer clip, call rtgui_win_update_clip more than
once will clip out all the widgets.

Thanks the bug report from haitao.
window: fix a memleak