Support python3

* Update indentation support;
* Python3 support;
* Removed pymode modeline support;
* Disabled async code checking support;
* Options changes:
    'pymode_doc_key' -> 'pymode_doc_bind'
    'pymode_run_key' -> 'pymode_run_bind'
    'pymode_breakpoint_key' -> 'pymode_breakpoint_bind'
    'pymode_breakpoint_template' -> 'pymode_breakpoint_cmd'
    'pymode_lint_write' -> 'pymode_lint_on_write'
    'pymode_lint_onfly' -> 'pymode_lint_on_fly'
    'pymode_lint_checker' -> 'pymode_lint_checkers'
    'pymode_lint_minheight' -> 'pymode_quickfix_minheight'
    'pymode_lint_maxheight' -> 'pymode_quickfix_maxheight'
    'pymode_rope_autocomplete_map' -> 'pymode_rope_completion_bind'
    'pymode_rope_enable_autoimport' -> 'pymode_rope_autoimport'

* Options removed:
    'pymode_lint_hold', 'pymode_lint_config', 'pymode_lint_jump',
    'pymode_lint_signs_always_visible', 'pymode_rope_extended_complete',
    'pymode_rope_auto_project', 'pymode_rope_autoimport_generate',
    'pymode_rope_autoimport_underlines', 'pymode_rope_codeassist_maxfixes',
    'pymode_rope_sorted_completions', 'pymode_rope_extended_complete',
    'pymode_rope_confirm_saving', 'pymode_rope_global_prefix',
    'pymode_rope_local_prefix', 'pymode_rope_vim_completion', 'pymode_rope_guess_project',
    'pymode_rope_goto_def_newwin', 'pymode_rope_always_show_complete_menu'

* Options added:
    'pymode_rope_regenerate_on_write', 'pymode_rope_completion', 'pymode_rope_complete_on_dot',
    'pymode_lint_sort'

* Commands added:
    'PymodeVirtualenv'

* Commands changed:
    'PyDoc' -> 'PymodeDoc'
    'Pyrun' -> 'PymodeRun'
    'PyLintToggle' -> 'PymodeLintToggle'
    'PyLint' -> 'PymodeLint'
    'PyLintAuto' -> 'PymodeLintAuto'
    'RopeOpenProject' -> 'PymodeRopeNewProject'
    'RopeUndo' -> 'PymodeRopeUndo'
    'RopeRedo' -> 'PymodeRopeRedo'
    'RopeRenameCurrentModule' -> 'PymodeRopeRenameModule'
    'RopeModuleToPackage' -> 'PymodeRopeModuleToPackage'
    'RopeGenerateAutoimportCache' -> 'PymodeRopeRegenerate'
    'RopeOrgamizeImports' -> 'PymodeRopeAutoImport'

* Commands removed:
    'PyLintCheckerToggle', 'RopeCloseProject', 'RopeProjectConfig',
    'RopeRename', 'RopeCreate<...>', 'RopeWriteProject', 'RopeRename',
    'RopeExtractVariable', 'RopeExtractMethod', 'RopeInline', 'RopeMove',
    'RopeRestructure', 'RopeUseFunction', 'RopeIntroduceFactory',
    'RopeChangeSignature', 'RopeMoveCurrentModule',
    'RopeGenerate<...>', 'RopeAnalizeModule', 'RopeAutoImport',