Length: wavelength - light sources
Fix Mock objects.
Return length object.

To avoid conflict, I did not use import...
Modify readers to support length quantity for wavelength.
Merge remote-tracking branch 'andrew/units-length' into units-length

Conflicts:
	components/formats-gpl/src/loci/formats/in/FV1000Reader.java
	components/formats-gpl/src/loci/formats/in/FlexReader.java
	components/formats-gpl/src/loci/formats/in/LIFReader.java
	components/formats-gpl/src/loci/formats/in/ZeissLSMReader.java
Modify initial commit introduced to avoid conflict.
Merge pull request #18 from jburel/units-length

Units length