test incremental building

[kjdon]

Someone other than david needs to test this.

• on linux, windows and mac.
• using lucene, mg and mgpp.
• adding new docs, changing existing docs _{and deleting docs.}

Command line forst, then in GLI. Have the minimal/full rebuild buttons been changed to use new incremental build?

DOes the old keepold still work? eg import some docs, delete them, and import some new ones with keepold, so as to do a manual incremental add.

[oranfry]

Fix incremental building so when metadata is added for the first time, the perl code detects this and re-indexes the affected file(s).

[kjdon]

tested all this and fixed bugs.

Can't guarantee no more bugs, but good enough for now.