Linkedin UI change. Fixed xpaths for all attributes

Hi Yatish,
               Linkedin has changed UI for public profiles last week. The current gem no longer works as the html parameters have changed. Hence, I have fixed most of them.
I couldn't fix for the following attributes : 
1) get_companies (Start date & End date). The date parsing fails when such dates are passed (5 years) i.e. no month is passed.
2) certifications (Authority & license). 
3) organizations (all attributes).

I might fix them later. They are not much used attributes currently. But we need to fix the rest.
Prefer double-quoted strings unless you need single quotes to avoid extra backslashes for escaping.