hwhw/kindlepdfviewer — pull request #515 by kai771 (2012-10-31 20:50:31+00:00)
Title: implements rtl_mode

Implements rtl_mode (rtl=right-to-left). Although I meant it mainly for reading manga, together with comics_mode, I guess it might be useful for other things too. Shortcut key is R. It’s only enabled in pdfreader and djvureader. It works in zoom modes fit-to-page-height, fit-to-content-height and 2 column mode.

This is the initial version, and possibly full of bugs. Please test thoroughly.

It also fixes a bug that was pressent in 2 column mode (at least I think it was a bug). In key_fw_left handling, there was a line:
```
if unireader.offset_x > 0 and unireader.pageno > 1 then
```
On the files I tested it with, unireader.offset_x was never 0 or less. So I changed this line to
```
if unireader.offset_x > unireader.pan_margin and unireader.pageno > 1 then
```
It appears to work for me, but I’m not really sure if it was the right thing to do, so @dpavlin, if you can please find the time to go through the code, I’d be most grateful.