talkatu/talkatu

Add a new TalkatuInput which subclasses TalkatuView and move the GSpell setup to it. Fixes TALKATU-60
# Building
Talkatu uses [meson](https://mesonbuild.com) as it's build system.
Meson requires you to build in a directory other than the source directory.
To compile you can use the following commands:
```
meson build
cd build
ninja install
```