Add features to fba_launch to support fiberassign on the fly

[schlafly]

A few fiberassign features making fiberassign on the fly at KPNO easier. This PR affects organization, permissions, and QA only, and doesn't actually change the contents of a fiberassign file, and so it should be low risk to merge.

• --worldreadable argument to fba_launch, makes permissions of output world readable, which is appropriate at KPNO.
• --svntiledir specifies an SVN output directory to which files should be copied. Files will be copied following the SVN root/ABC/fiberassign-ABCDEF convention.
• Whitespace changes (sorry, my editor did this without my noticing, mea culpa).
• Bug fix for querying images from viewer for tiles for tile qa.