Add fancy build status buttons!

everyone else is doing it... :P
fixes #1053, fixes #924
fixes #836
fixes #1666
Merge pull request #1665 from flaviut/patch-1

Add fancy build status buttons!
fixes #1562, fixes #1543
Merge branch 'devel' of https://github.com/Araq/Nimrod into devel
fixes #916
fixes #939
fixes #837
fixes #1669
more robust against unknown line info
fixes #1337
fixes #642
fixes #1672
fixes #1547
fixes #1657
doc improvements
fixes #1539
Merge branch 'devel' of https://github.com/Araq/Nimrod into devel