build.xml and tests/build.xml:
updated general format to match what is generated in a new project.
moved targets common to both to build_common.xml.
replaced some exec calls (perl, mv) and inline javascript with ant tasks (including extensions from Android and ant-contrib).
build.xml:
fixed indentation.
privatized targets that don't need to be called directly from command-line.
renamed some properties.
tests/build.xml:
renamed test project from K9 to K9Tests.
tools/ant-contrib.jar:
new!
.gitignore:
added note about local per-repo rules.
