Wire library doesn't support clock skew. [imported]

This is [Issue 334](http://code.google.com/p/arduino/issues/detail?id=334) moved from a Google Code project.
Added by 2010-08-22T01:00:36.000Z by [erdem...@gmail.com](http://code.google.com/u/116271074955560184100/).
Please review that bug for more context and additional comments, but update this bug.

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

**What change would like to see?**
I wanted to see clock_skew support.
**Why?**
Because slaves might needed to make some job that takes long time. So If we drive SCL low, than master knows that slave is busy.

**Would this cause any incompatibilities with previous versions? If so, how**
**can these be mitigated?**
No, it doesn't cause any incompatibility.