All of the bit logic in CI routines no longer relies on any integer types for intermediates, so any number of active orbitals can now be used (so long as nbit__ is set appropriately). The operation count is probably about the same too. Confirmed to work for CIS with > 64 orbitals. The limitation now is that the Comb class only provides binomial coefficients up to 31.
Merge branch 'master' of https://github.com/shiozaki/BAGEL

# By Toru Shiozaki (2) and Ryan Dave Reynolds (1)
# Via Ryan Dave Reynolds
* 'master' of https://github.com/shiozaki/BAGEL:
  To compile with Clang - Resolves #33
  minor comment fix
  fine tuning and minor bug fixes in new mp2
comb extended up to 64
Merge branch 'master' of https://github.com/shiozaki/BAGEL