as lua code may request ffi load of library like "libfreetype.so.6"

- based on https://github.com/SufficientlySecure/document-viewer/blob/master/document-viewer/src/main/AndroidManifest.xml
- fixes koreader/koreader#3006 for PDFs (tested using the approach written in the issue; I did not build the app by myself, just changed this file in the .apk)
- I added other mimetypes based on the supported file types as written in https://github.com/koreader/koreader/blob/master/README.md but couldn't test them; you might want to add more

See comment #55 (comment)

* obtain Status bar height
* obtain screen size

No Android build due to typo. Fixes koreader/koreader#3038

To prevent XML well-formedness issues like in 2c40b08.

There are different numbers all over the place, but I *think* the code points toward Android 4 (platform-14) as an intended target.

Also, by using `NDKABI=${NDKABI:-14}` we allow for environment variable overrides. It only sets the default of 14 if $NDKABI isn't set. This is in the same spirit as koreader/koreader#3064

The comment in mk-luajit.sh misled me. Everything builds under ABI 9 so there's no reason to enforce 14.

also hide navigation bar on start

In:
* android.lua

* launcher.lua

* install.lua

Can create an x86 package combined with  koreader/koreader-base#544

References koreader/koreader#1815

You'll need to manually `./mk-luajit.sh clean` in between builds
for different architectures for the moment.

Fixes koreader/koreader#3126

Thanks to @chrox for testing, see koreader/koreader#3126 (comment).

…e a full screen (#70)

This should fix the x86 Android build on Gitlab.

These lines enabled us to find the issue for Android 8 and will allow for more immediately useful logs in the future.