String change in Yelp

[Shaun McCance <shaunm gnome org>]

I've commited the patch from Seán de Búrca on bug #505797.
The following strings changes were made as a result:

"Learn more about making you're system more accessible for
 a range of disabilities"
"Learn more about making your system more accessible for
 a range of disabilities"

"Settings users can manipulate to make their environment
 more pleasent"
"Settings users can manipulate to make their environment
 more pleasant"

"Tools to help you manage you're computer"
"Tools to help you manage your computer"

"Licences"
"Licenses"

--
Shaun