Build SCIFIO using Java 1.6
Remove @see comments

These comments are burdensome to maintain as they quickly fall out of
date when the code is refactored. And they are unnecessary with modern
IDEs anyway, thanks to knowledge of the AST (e.g., ^T in Eclipse).

This was done using the script:
https://github.com/ctrueden/ctr-scripts/blob/master/one-offs/non-javadoc-purge
Add missing @Override annotations
Merge branch 'java-6'

Updates SCIFIO to use the maven compiler configuration specified in the
pom-scijava parent (currently Java 6).

Removes all "/* @see */ comments for interface-backed methods in abstract and
concrete classes that do not override a superclass method, and adds @Overrides
in their place (as this causes the Java 1.5 compiler to complain).

Closes issue #50