bugfix to baseUrl handling
decrease default chunksizelimit for vcf files to 1mb
fix subtle VCF bug
tweak config system to evaluate hooks after doing variable templating.

also, write some of the volvox example callbacks in a separate file, and
include it in the tracklist.json
refurbish gbrowse-like conf adaptor, use it for another separate functions file
just use the gbrowse-like adaptor as the primary separate-functions file
update release notes to point out .conf format
port jbrowse_conf.json to gbrowse-style conf syntax
rewrite gbrowse conf adaptor to support more than 2 levels of nesting
add support for embedded JSON and arrays (via +=) to conf format
Merge remote-tracking branch: upstream/master