Add ability to disable RX or TX when using SoftwareSerial. [imported]

This is [Issue 902](http://code.google.com/p/arduino/issues/detail?id=902) moved from a Google Code project.
Added by 2012-04-26T04:40:25.000Z by [d...@skylab2000.com](http://code.google.com/u/105619286601756564648/).
Please review that bug for more context and additional comments, but update this bug.

Original labels: Type-Defect, Priority-Medium
### Original description

**What steps will reproduce the problem?**
1. see below
**2.**
**3.**

**What is the expected output? What do you see instead?**

n/a

**What version of the Arduino software are you using? On what operating**
**system? Which Arduino board are you using?**

1.0, Uno.

**Please provide any additional information below.**

Shouldn't the option to disable TX or RX be written into SoftSerial?