Merge pull request #92 from simpleinvoices/2013.1.beta.5

2013.1.beta.5 merge
Merge pull request #99 from simpleinvoices/2013.1.beta.6

2013.1.beta.6 merge
Update readme.md
Merge pull request #104 from simpleinvoices/master

Updated readme.md for SI 2013.1.beta.6 download link