Update koreader.po

Update Polish translation from transifex
Merge pull request #551 from danan72/patch-2

Update koreader.po
Update koreader.po
Merge pull request #554 from th0mass/patch-1

Update koreader.po (tr)
wtest crashed: ./luajit: ./frontend/document/credocument.lua:21: attempt to index global 'G_reader_settings' (a nil value)

A little copy-paste from reader.lua has it working again.
Delete wtest.lua.bak

I fucked up with pushing. I'll reread github tutorial. Sorry!
1. wtest.lua crashed. So I cut&paste some lines from reader.lua to fix it.
2. I added the function TestVisible to assess the extreme coordinates still visible on the Kobo Aura.
Merge pull request #555 from Markismus/master

wtest.lua adapted for use with issue #372
add koreader plugin mechanism
This should implement #505.
add Evernote plugin to export highlights and notes

The "My Clipping" file that storing highlights and notes for Kindle
native readers could also be parsed and exported. The parser is
implemented in `evernote.koplugin/clip.lua`.

Parsed highlights and notes in one book will be packed and rendered
into html node with a slt2 template `note.tpl` that complies with
evernote markup language(ENML).

Finally the evernote client will create or update note entries and
push them to Evernote cloud.