Edit book: Fix option to disable showing the character before cursor not working
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Fix Bug #1268118: epub converted produces invalid .rtf file
Fix amazon store plugins not showing cover.
Fix kobo store not showing any results.
Fix smashworks store not showing any results.
Remove eharlequin store because it no longer works.
Update store versions.
Make the installer run non-interactively with installation dir specified via environment variable
RTF Output: Fix invalid RTF being produced when the text contains a double backslash. Fixes #1268118 [epub converted produces invalid .rtf file](https://bugs.launchpad.net/calibre/+bug/1268118)

Also updates to various Get Books plugins

Merge branch 'master' of https://github.com/user-none/calibre