POM: extend pom-scijava

The pom-scijava parent POM provides lots of technical benefits,
including many configuration convenience blocks, as well as
workarounds for various bugs, etc. By extending pom-scijava,
Bio-Formats automatically inherits this helpful configuration, so
that it can avoid painfully encountering all the same issues which
have already been solved in other SciJava projects.

On a social level, extending pom-scijava also signifies that the
Bio-Formats project is part of the SciJava software stack.

Since the org.scijava:pom-scijava artifacts are now available in
Maven Central, there is no more issue with this dependency resulting
in any reference to the maven.imagej.net Maven repository.
POM: remove no-longer-needed configuration blocks

The pom-scijava parent declares all the same things,
so there is no need to repeat them downstream.
POM: remove unneeded .git suffixes
POM: fix whitespace and style
POM: depend on the correct ImageJ 1.x GAV

The nih.gov.imagej GAV is obsolete and deprecated. Furthermore, it uses
an incompatible artifact name, resulting in both "ij-" and "imagej-"
artifacts on the classpath of anything that seeks to use Bio-Formats as
a dependency.

Since the net.imagej:ij:* artifacts are now available in Maven Central,
there is no more issue with this dependency resulting in any reference
to the maven.imagej.net Maven repository.
POM: simplify license-maven-plugin configuration

We no longer need the local license resolver, since the Simplified BSD
license has been added to the list of built-in licenses.
Put original JAI Image I/O copyright in a NOTICE

The NOTICE file, rather than LICENSE, is usually the place where
third-party license blurbs go, to avoid polluting our LICENSE.
Update licenses

This was done using:
    mvn license:update-project-license
    mvn license:update-file-header

The main difference is the loss of the disclaimer at the bottom
of each BSD-2-licensed file. For discussion and rationale, see:
    https://jira.codehaus.org/browse/MLICENSE-80

There were also a few files missing the header, as well as a few missing
LICENSE.txt files, both of which have been corrected by this update.