configure.ac: remove superfluous bracket

Reported-by: Cory Fields
Cleanup code by using forward declarations and other methods of avoiding unnecesary header includes

Fix build error, cleanup CSecret artifact, and change main.h include to core.h
Remove cstdio references, depend on util.h instead.
Replace manual typedefs with stdint.h, replace PRI64[xdu] with PRI[xdu]64 from inttypes.h

Fix build problem hopefully.
Minor modifications after rebase.
Update extract_strings_qt.py to produce better formatted code file.
Change new [u]int64s to [u]int64_ts
Include missed main.h change.
Address minor nits, normalize QT_VERSION ifs where possible.
Fix build errors
Fix rebase to match previously merged version.