Added function as_header to oauth1.0_token

Same default as before, but is param as_header = FALSE is added then it
adds as parameter to url.
Added demo for withings

A small demo on how to use as_header to access withings API.
Updated style and added news

Fixed some styles issues and added a bullet point to the news. Also
fixed a typo in params explanation.
Added function as_header to oauth1.0_token

Same default as before, but is param as_header = FALSE is added then it
adds as parameter to url.
Added demo for withings

A small demo on how to use as_header to access withings API.
Updated style and added news

Fixed some styles issues and added a bullet point to the news. Also
fixed a typo in params explanation.
Merge remote-tracking branch 'origin/master'

Conflicts:
	NEWS.md
Added news
Fixed news
Merge pull request #150 from Bogstag/master

Added as_header parameter for oauth1.0_token