Initial checkin of .gitattributes.  This is the way to suppress files in the distro.

Leo build: 20141016124133
More changes/experiments with .gitattributes

Leo build: 20141016124527
.gitattributes now suppress all files that were formerly suppressed.

Leo build: 20141016125220
Removed ancient pylint-leo.bat

Leo build: 20141016132451
Removed still more files from the distro.

Leo build: 20141016132551
Undo lots of changes to LeoPyRef.leo

Leo build: 20141016134318
Mysterious change to LeoPyRef.leo during build process.

Leo build: 20141016134501
Many changes to leoDist.leo preparing for Leo 5.0.
- The distribution script now uses git instead of bzr:
1. gitattributes controls whether files are written to the .zip file.
2. git-manifest.txt controls the files listed in nsi-install.txt and nsi-uninstall.txt.

Leo build: 20141016134815