portRead() and portWrite() commands, if possible. [imported]

This is [Issue 247](http://code.google.com/p/arduino/issues/detail?id=247) moved from a Google Code project.
Added by 2010-05-06T18:33:13.000Z by [dmel...@gmail.com](http://code.google.com/u/107726014984682000895/).
Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Enhancement, Priority-Medium, Component-Core
### Original description

**What change would like to see?**

portRead() and portWrite() functions. Although given that the pins in the ports aren't necessarily all
available or contiguous, we'll have to figure out some of the details.

**Why?**

So you can read and write the whole port at once - for speed, and eliminating some potential
problems.