Add transparent input decompression

This supports gzip and bzip2 by magic number determination.

Trailing whitespace differences in documentation due to opinionated
editor.
Add tests for decompressor
Merge pull request #71 from kortschak/compress

Add transparent input decompression
Switch to the latest mgo path.

This is not only the right thing to do, as per the documentation of the
latest release (yesterday) but it should now be backed by git and not
bzr, which is a big plus and won't break our build so much.
Merge pull request #76 from barakmich/master

Switch to the latest mgo path.
Merge branch 'master' into parse

Conflicts:
	db/load.go