Revert custom iOS changes, use fatlib, update .gitignore

.gitignore

@@ -5,54 +5,6 @@
 /.buckconfig.local
 /.buckd
 /gentest/test.html
-.buckversion
 
 # Visual studio code
 .vscode
-*.pdb
-*.tlog
-*.obj
-*.pch
-*.log
-*.orig
-
-# Xcode
-## Build generated
-build/
-DerivedData/
-
-## Various settings
-*.pbxuser
-!default.pbxuser
-*.mode1v3
-!default.mode1v3
-*.mode2v3
-!default.mode2v3
-*.perspectivev3
-!default.perspectivev3
-xcuserdata/
-
-## Other
-*.moved-aside
-*.xcuserstate
-
-## Obj-C/Swift specific
-*.hmap
-*.ipa
-*.dSYM.zip
-*.dSYM
-
-# CocoaPods
-#
-# We recommend against adding the Pods directory to your .gitignore. However
-# you should judge for yourself, the pros and cons are mentioned at:
-# https://guides.cocoapods.org/using/using-cocoapods.html#should-i-check-the-pods-directory-into-source-control
-#
-Pods/
-
-# Carthage
-#
-# Add this line if you want to avoid checking in source code from Carthage dependencies.
-# Carthage/Checkouts
-
-Carthage/Build