I have these badges in my Github repo:
How can I make them align to left (the 2 above) and to right the one under?
They are in the format 
One way would be to use html table (since markdown table in GFM doesn't support merged cell)
this, for instance, seems to align the pictures properly within a README.md
file.
<table >
<tr>
<td align="left"><img src="http://icons.iconarchive.com/icons/iconka/cat-commerce/48/add-icon.png"/></td>
<td align="right"><img src="http://icons.iconarchive.com/icons/iconka/cat-commerce/48/info-icon.png"/></td>
</tr>
<tr>
<td colspan="2"><img src="http://icons.iconarchive.com/icons/shwz/disney/512/pumbaa-icon.png"/></td>
</tr>
</table>
Result:
In your case:
<table>
<tr >
<td><img src="https://api.travis-ci.org/axemclion/grunt-saucelabs.png?branch=master"/></td>
<td align="right"><img src="https://saucelabs.com/buildstatus/grunt-sauce"/></td>
</tr>
<tr>
<td colspan="2"><img src="https://saucelabs.com/browser-matrix/grunt-sauce.svg"/></td>
</tr>
</table>
Which gives: