There are quite a few changes, mostly bug fixes and improvements, plus a few additions. There are still a few things I need to fix. I will update this post with a summary of the changes before merging.
Summary
Add menu item for reinitialising the TTS engine.
Add settings screen for setting and changing app-specific TTS settings.
Change minimum required Android version to Android 5.0 Lollipop.
Change output sound file names to use the '.wav' extension instead of '.mp4'.
Change the app to handle input lines and text files longer than Android's maximum speech input length.
Improve TTS initialisation and language handling.
Make TTS notifications display process of text synthesis.
Closes #1, #2, #4, #6.
There are quite a few changes, mostly bug fixes and improvements, plus a few additions. There are still a few things I need to fix. I will update this post with a summary of the changes before merging.
Summary