Remove trailing whitespace from JPM tooltips

When the tooltips for JPM resources are rendered in Eclipse (at least on
Windows), the trailing newlines cause them to be 1 line taller than they
should be.  So trim them before returning them.

Also changed one place where string concatenation was used when a format
string should have been.

Signed-off-by: Sean Bright <sean@malleable.com>
Merge pull request #607 from seanbright/jpm-tooltip-cleanup

Remove trailing whitespace from JPM tooltips