Bugfixes
-fixed #28
-fixed #30

Coordinator.java:
-disabled termination email for now (until a fix is found for the blocking shutdown hook)

Prefs.java:
-changed default config file to ""
-updated readPreferences() to allow null and blank argument (only default prefs will be used)
-updated savePreferences() to remove check for overwriting default preferences file

SettingsHandler.java:
-updated to remove check for overwriting default preferences file

HeadLessTest.java:
-re-enabled test since ant build file runs separate test in headless environment

XmlFormatterTest.java:
-updated to validate generated xml from schema file

index.css:
-added additional padding to top of settings main content

build.xml:
-added target to test headless classes