Off-the-Record Messaging Plugin for Psi IM and Psi+

To compile the plugin you need to have installed the following libraries:
    - Qt 5.x (https://www.qt.io/)
    - libotr (https://otr.cypherpunks.ca/)
    - TidyLib (http://tidy.sourceforge.net/)

Perform the following steps:

- Get Psi+ and apply the patches to the latest sources of Psi. Therefore you can
  use one of the scripts provided by Psi+.

- Make the Psi/Psi+ include files available to the plugin. To achieve this, copy
  the psi-otr-X.X/ directory to the src/plugins/generic/ directory of your
  patched Psi/Psi+ source tree.
 
- change to the psi-otr-X.X/ directory and run qmake to generate a Makefile:
  $ qmake

- Then run make to compile everything:
  $ make

The resulting binary is libotrplugin.so or otrplugin.dll. This file should be
copied to the plugins subdirectory of the Psi+ resources:
* /usr/lib/psi-plus/plugins/ or /usr/local/lib/psi-plus/plugins/ or
  ~/.local/share/psi+/plugins on Linux-based and FreeBSD systems
* C:\Program Files\Psi+\plugins\ or %PSI_PLUS_DIRECTORY%\plugins\
  on MS Windows systems

Build and installation in Mac OS X is possible as well, but it requires some
magic.

If you have successfully installed OTR plugin, do the following steps when you
run Psi+ for the first time:
- Enable the plugin in the 'Options'-->'Plugins' dialog and click on 'Apply'.
- Set the OTR policy in the 'Config' Tab of the plugin options.
  In most cases 'Automatically start private messaging' should be a good choice.
- There is no button etc. to generate your private key. It will be generated
  when it's needed. I.e. when you start your first private conversation.

