Merge pull request #53 from Michagogo/master

Michagogo's gitian sigs for v0.9.3rc1
Replace outdated excerpt of release process with links
Andreas' signatures for 0.9.3rc1.
Merge pull request #54 from schildbach/sigs-0.9.3rc1

Andreas' signatures for 0.9.3rc1.
laanwj sigs 0.9.3rc2
Gavin 0.9.3rc2 builds
fix up directory name for linux

0.9.3rc2-linux -> 0.9.3rc2

Having them in separate directories harder to compare.
Don't use the new convention yet for 0.9.3.
Michagogo's gitian sigs for v0.9.3rc2