sort template data so resulting mainfile is consistantly reproducible,
which is important to leverage build cache and results in a consistent
build id on output (given identical build parameters, e.g. ldflags,
output file name, etc.)

Result of `mage -compile ./mage_static && go tool buildid ./mage_static`
should now always be identical on repeated invocation.

Results in a probably imperceptible build time quickening, but solves a
minor peave of mine, and adds a test as protection from regression :)

Co-authored-by: Nate Finch <nate.finch@gmail.com>

got caught out not using vim's spellcheck

Co-authored-by: Paul Burlumi <paul@burlumi.com>

got caught out not using vim's spellcheck

Co-authored-by: Paul Burlumi <paul@burlumi.com>

Co-authored-by: Paul Burlumi <paul@burlumi.com>