Metacat

After changing the version depency on the metacat-index pom.xml and some code change, the new version works.

There is an issue here:

how can we copy the new schema.xml to overwrite the existing /solr-home/conf/schema.xml?

Here is my thought:

1. During the configuration (installation), the hash of the existing schema.xml will be calculated.
2. If the hash value indicates that the schema.xml wasn't changed, the installation process will overwrite the existing one silently. I guess the possibility of the case will be more than 90%.
3. If the schema.xml was changed, we should show a message to ask the user manually merge the difference and put the new one into the place.