[FIRST] plotlyupdate.m

@chriddyp wanna look this over when you get a chance. 

plotlyupdate
plotlyupdate('verbose') 
ploltyupdate('verbose','nocheck') 
could we change, maybe, to:
```
Shoot! We tried to copy the Plotly folder into the MATLAB toolbox directory, but were denied write permission. You'll have to add the Plotly folder to your MATLAB path manually by running, e.g.

>> plotly_path = fullpath(pwd, 'plotly')
>> addpath(genpath(plotly_path))

Questions? Chuck@plotly
```
(is that `plotly_path` right?)