Add an NIO service for working with ByteBuffers

This service addresses the same need that NIOByteBufferProvider
previously did, but in a context-sensitive way.

This commit also uses the new NIOService API as appropriate throughout
the codebase.
Move QuickTime classes to io.scif.formats.qt

These classes go together, to support QuickTime movies and PICT images.
Repurpose LegacyQTTools as QTJavaService

The LegacyQTTools were intended to function in a manner very consistent
with how SciJava services work, so it is a natural fit.

It also allows the QTJavaService easier access to the LogService, among
other benefits.
RandomAccessInputStreamTest: use minimal context