#99: Windows build.properties contains shell script error instead of com...

...mit ID in build_revision field.

This contains the following fixes:

1. Add a line to .gitattributes to force sh scripts to get checked out with LF line endings.
2. Change pom.xml to call the get_build_revision.sh script via a relative path instead of prepending the Maven basedir.

I have tested this by running the build on both Linux and Windows.  Both created a good build.properties.

@sjlee, would you please take a look?  Thanks!