Fixed bug in chrome, which caused bootsrap buttons to have a of height of 33px instead of 34px

Hi there,

I had a strange bug today in my chome browser which caused bootrap buttons to be 33px heigh instead of the usual 34px. After some research, I found out that its a know issue and can be fixed by increasing the the precision of the sass compiler.

Cheers,
Peer

Found cause and fix here: 
https://github.com/thomas-mcdonald/bootstrap-sass/issues/409
https://github.com/gruntjs/grunt-contrib-compass/issues/113