543815: Mylyn should use buffered output streams

Buffered output streams and replaced try-finally with try resource

Change-Id: I504647dc1a608df3502158eded47a917e9be37df
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=543815
Signed-off-by: Natasha Carson <natasha.carson@tasktop.com>