Rename core to geode and start making install easier

Geode's c++ and python components will install separately: scons
manages the c++ install into standard locations such as
/usr/local/include and /usr/local/lib, and python's setuptools
manages the python python part.  This adds an extra step for users,
but makes the management of downstream c++ code much easier (no need
to find hidden c++ headers under site-packages and such).

The following commands were used in the core to geode rename:

  perl -pi -ne 's/<other\/core\//<geode\//g;' `find -name \*.h -o -name \*.cpp`
  perl -pi -ne 's/(from|import) other\.core/$1 geode/g;' `find -name \*.py` `scripts`
  perl -pi -ne 's/OTHER_/GEODE_/g;' `find -name \*.h -o -name \*.cpp`
  perl -pi -ne 's/namespace other\s*{/namespace geode {/g;' `find -name \*.h -o -name \*.cpp`
  perl -pi -ne 's/\bother::/geode::/g;' `find -name \*.h -o -name \*.cpp`
  perl -pi -ne 's/\bnamespace other\b/namespace geode/g;' `find -name \*.h -o -name \*.cpp`
  perl -pi -ne 's/USE_OPENMESH/GEODE_OPENMESH/g;' `find -name \*.h -o -name \*.cpp`
Remove last references to OTHER
README.md: Rewrite for new standalone geode
Merge remote-tracking branch 'origin/master'
Fix for downstream use