Update readme

README.md

@@ -1,35 +1,42 @@
 # Stellarium-android
-A version of Stellarium for android
+A modded version of Stellarium-Mobile
 
-Original readme document has been renamed to README
-
-Original source code: http://stelladata.noctua-software.com/stellarium-mobile/stellarium-mobile-1.24.tar.gz 
-(This link is dead now...)
+Stellarium kernel version 0.12.3
 
+Mobile platform specific source code http://stelladata.noctua-software.com/stellarium-mobile/stellarium-mobile-1.29.tar.gz 
 Assets from https://code.launchpad.net/stellarium/
+Note that changes have been made to the source code and assets (mainly use uncompressed PC version assets instead of compressed ones)
 
 Copyright: Original Stellarium dev team
 
+## Features
+* Extend default star catalog limiting magnitude to 13.5
+* Allow custom configuration files and catalogs (Put them in ```/sdcard/stellarium```. Same file structure to ```mobileData/data```)
+* Tweak UI size for better handling on mobile
+* Correct for magnetic declination angle (Magnetic North is not real North)
+* Higher quality texture compared to official Stellarium-Mobile
+
 ## Prerequisites
-Qt-for-android (preferably qt 5.6 or higher)
+* Qt-for-android (Known to work on qt-5.11 and 5.12)
 
-Since qt does not provide a redistributable version of qt-for-android, you
-may have to build it for yourself. The building procedure is already 
-detaily documented in the document of qt. Please refer to qt.io for info.
+Please note that for version ealier than 5.10, API for permission models for Android 6.0+ were not correctly implemented in Qt.
+Notably, Qt did not provide any API for requesting ```read/write to external storage``` permission. This permission is essential
+to the application.
 
-Python PIL
+## Building APK
+Set up android SDK and NDK, and environment in QtCreator.
+Open ```stellarium.pro``` in QtCreator.
+Push the Build button.
 
-If you want to create low-resolution resources, please run 
-create-mobile-data.sh. It will call PIL so you might want to have it installed 
-firsthand.
+If the building process runs into problems while compiling ```dummy.cpp```, simply copy the file to build directory and rename it ```moc_predefs.h```.
 
-## Installation
-The original INSTALL file nearly states nothing useful, but some links are 
-still provided within that document. Simply download and build. I have 
-included all assets in this respository as I might modify them in the 
-future.
+## Localization guide
+TODO
 
 ## Change Log
+### April 3, 2019
+Update to mobile source code to 1.29.6
+Clean up unused files
 ### June 21, 2018
 Android 8.0 support
 Runtime permission request