FEAST-EOM-CCSD and RT-EOM-CCSD

This is a release involves the following breaking changes:

• Dependency on CTF is completely removed, since the upstream CTF python lib is not so well maintained
• Added two new algorithms based on Cauchy integral formula for excited states: FEAST-EOM-CCSD and RT-EOM-CCSD
• Introduced a modified PySCF as a new dependency