fmt update

Fix: Placed all +build tags in the same location
Fix: Split CFLAGS, LDFLAGS into seperate lines for readability and lookup
Fix: Placed empty line between copyright comments and build tags for readability
Fix: Placed OS specfic cgo flags at the end if the cgo sections contains multiple lines.

sqlite3_usleep_windows.go

@@ -1,10 +1,10 @@
-// +build cgo
-
 // Copyright (C) 2018 G.J.R. Timmer <gjr.timmer@gmail.com>.
 //
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
 
+// +build cgo
+
 package sqlite3
 
 // usleep is a function available on *nix based systems.