[pdal] reader text file

[Howard Butler]

> On Dec 3, 2015, at 8:53 AM, Andrew Bell <andrew.bell.ia at gmail.com> wrote:
> 
> I think we already have this.  It's called filters.programmable.

Except that filters.programmable doesn't define a PointTable/PointView. It can only operate inline. 

A simple readers.text that takes in just plain doubles, a map of dimension names, and does no magical data munging would be really useful. Combined with readers.python, I think we would have the majority of the use cases covered.

Howard