Git related packaging script changes

Bump the version to 2.0.0 as previously discussed.

Similar to the adapter plugin, replace BZR_REVISION with GIT_COUNT and GIT_HASH. The former being the count of merges (increasing, generally by 1 with how we deal with master) and the latter being the short hash. Minor other changes, mostly in build_packages.sh, to get files set up and variables passed around.

Note that client tools is still sourced from LP. That will change with the rename branch.

I tested building rpm, deb and dmg. I'll cross my fingers for the exe.