text viewer: reworks screen access logics and some bugs fix.

- screen access logics separte from tv_window. (new tv_display.[ch])
- using multi screen api.
- (bug fix) the head of the each line is not normally displayed when the alignment is RIGHT.
- (bug fix) unnecessary blank line is not displayed. (a part of FS#11400).
- (bug fix) the order by which callback functions were called was not correct. (FIFO->FILO)

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27138 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/text_viewer/SOURCES

@@ -1,6 +1,7 @@
 text_viewer.c
 tv_action.c
 tv_bookmark.c
+tv_display.c
 tv_menu.c
 tv_pager.c
 tv_preferences.c