Release 1.0.4

Release 1.0.3

Release 1.0.2

Release 1.0.1

Add semver (miekg#595)

Add a version.go that has the semver version of this libary; now at
1.0.0. Use a struct so external code can easily check the for the
version without resulting to string parsing. Add String() function if
you want to access the version string.

Use simple Makefile.release to kick off a new release:

% edit version.go
% make -f Makefile.release

will tag and push according to version, if version is 1.0.0 the tag
in git will be v1.0.0