Ubuntu Fixes for Google TTS Support

[JaredF]

Closes #446.

The primary fix here for Ubuntu is to add the parameter 'sound_converter' which allows the user to specify the program to be used for converting the mp3 files to wav format. In Ubuntu, the name of the ffmpeg program was changed to avconv while still accepting the same flags/parameters. I have left ffmpeg as the default for backwards compatibility for anyone that is currently using this feature.

I also slightly changed the system call to play the sound file generated to be compatible with 'sound_program' parameters that include flags incorporated with the sound program name.

Finally, I used the preexisting voice parameter 'language' to allow the user to select the language of the voice that Google will use to create the audio file.

I really like this feature as a TTS option because it requires no extra software on the part of the user and minimal configuration in MH to get quickly up and running. Thanks to @progeek for the initial commit.

[JaredF]

I put the wrong issue number in the original commit message and can't figure out how to remove/correct it. Please ignore.

[krkeegan]

@JaredF if you could add some brief documentation to the bin/mh.ini file concerning sound_converter all of our future selves will be eternally grateful to you.

[JaredF]

@krkeegan, will do. Speaking of documentation, do we have a location that we currently use to document the list of supported TTS engines and the configuration parameters required for each option? All I can find is what is mentioned in: http://misterhouse.sourceforge.net/install.html

[krkeegan]

I have not graduated to TTS yet, so I haven't looked into the documentation. But if that is all you can find, that is probably all there is.

[hollie]

On OS X TTS works out of the box with the built-in TTS engine. Only disadvantage is that it only works on the machine that is running MisterHouse. I haven't found time to look into forwarding the generated audio to other devices.

[JaredF]

I'm going to go ahead and merge this one in since it only adds enhancements and should not break anything for users currently using this TTS engine.