Added externs for additional Wire instances#97

Merged

sandeepmistry merged 2 commits intoarduino:masterfrom

spiderkeys:master

Jan 20, 2016

Commits on Jan 19, 2016

Added externs for additional Wire instances
Charles Cross
committed
Followed the precedent in SPI and Wire libraries, adding #ifdefs to conditionally declare Wire interface externs
Charles Cross
committed