Fix a bug in pclearbot

Fix a bug in pcofix with handling hypotheses with existential quantifiers

• Bug fixes in pcofix, gcofix and pclearbot

• Remove hppattern.v (#47)
• Fix a variable renaming bug

• Remove warnings

• Fix pcofix tactic bug (#41)

• Fix pcofix tactic bug (#37)
• Remove JMeq_eq axiom (#34)

• Fix pcofix tactic (#34)
• Remove dependency of gpaco on JMeq_eq

• Fix a bug in the pcofix tactic
• General respectful closures

• Fix gpaco tactic (#37)