Add .template extension to template files

While the source install doesn't have this issue, I have been experimenting with packaging ROS in RPMs for Fedora. The RPM build process bytecompiles all python code, and the script finds the template and tries to compile it.

This is the first time I've hit this problem, but this is the only sensible fix for it. I tested this against a Fedora source install and everything LOOKS good, but it should be tested on Ubuntu/Mac before pulling, as it is a fairly small commit, but large change.

Any other suggestions would be appreciated.

Commit Details:
The template files do not contain valid syntax...yet. Therefore it is not appropriate to give them .h/.py extensions.
The primary motivation was found when byte-compiling python code automatically. To do this in Fedora, the script searches for files ending in .py and tries to bytecompile them, which fails on the python template file with its current name.