specification: Rename additions/jar to external

For use by the C++ code where this name is inappropriate in the
install tree.
specification: Add XML catalogues for all released XML schemas
Merge remote-tracking branch 'origin/develop' into specification-catalogue2
cpp: ome-xml: Install external schemas and catalogue files
Add guava to the bundle jars
Fix base64 decoding

This limits the number of bytes read, so that the entire stream is not
decoded for every plane.  It also removes the extra encoding step in
favor of trimming the already-encoded base64 string at the first "<".
Set the encoding to ASCII to handle units.

The sample files should now work.
Merge pull request #20 from jburel/ome-xml-fix

Set the encoding to ASCII to handle units.
OME-XML: prevent IndexOutOfBoundsException if BinData is empty
Merge branch 'ome-xml-fix' of github.com:melissalinkert/bioformats into ome-xml-fix
PNG: reduce the amount of memory needed to read most tiles

The very last row of tiles will still require the full image to be
read, however.
cpp: xerces: Throw exception on EntityResolver failure
cpp: test: Update xerces schema paths
Merge remote-tracking branch 'origin/develop' into specification-catalogue
Merge branch 'cpp-xercesfix' into specification-catalogue
Handle empty binData tag.
Merge pull request #21 from jburel/ome-xml-fix

Handle empty binData tag.
PNG: use a custom InputStream implementation for decompressing images

This prevents us from having to read the entire compressed stream into
memory before decompressing.  See #12274.
specification: Add missing catalogue for 2007-06 schema
specification: Add missing xml.xsd entity to external catalogue