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.
sqlite_omit_load_extension is a go build tag which behaves much like its
C counterpart SQLITE_OMIT_LOAD_EXTENSION
Signed-off-by: Jessica Frazelle <acidburn@docker.com>