[REF] removed explicit model instanciations.

addons/account/account.py

addons/account/account_analytic_line.py

addons/account/account_bank_statement.py

addons/account/account_cash_statement.py

addons/account/account_financial_report.py

addons/account/account_invoice.py

addons/account/account_move_line.py

addons/account/company.py

addons/account/installer.py

addons/account/ir_sequence.py

addons/account/partner.py

addons/account/product.py

addons/account/project/project.py

...account/project/wizard/account_analytic_balance_report.py

addons/account/project/wizard/account_analytic_chart.py

...wizard/account_analytic_cost_ledger_for_journal_report.py

...unt/project/wizard/account_analytic_cost_ledger_report.py

...roject/wizard/account_analytic_inverted_balance_report.py

...account/project/wizard/account_analytic_journal_report.py

...s/account/project/wizard/project_account_analytic_line.py