User key bindings for sublime text and modificated duplicate_line.py in /Packages/Default/duplicate_line.py

Default (OSX).sublime-keymap.json

[
	{ "keys": ["super+g"], "command": "find_under", "context":
		[
			{ "key": "selection_empty", "operator": "equal", "operand": false, "match_all": true }
		]
	},
	{ "keys": ["super+c"], "command": "noop", "context":
		[
			{ "key": "selection_empty", "operator": "equal", "operand": true, "match_all": true }
		]
	},
	{ "keys": ["super+d"], "command": "duplicate_line", "args": {"force_lines": true}},
	{ "keys": ["shift+enter"], "command": "run_macro_file", "args": {"file": "Packages/Default/Add Line.sublime-macro"} },
	{ "keys": ["super+shift+x"], "command": "run_macro_file", "args": {"file": "Packages/Default/Delete Line.sublime-macro"} },
	{ "keys": ["super+k", "super+m"], "command": "set_mark" },
	{ "keys": ["alt+up"], "command": "swap_line_up" },
	{ "keys": ["alt+down"], "command": "swap_line_down" },
	{ "keys": ["ctrl+q"], "command": "previous_edit" },
	{ "keys": ["ctrl+shift+q"], "command": "next_edit" },
	{ "keys": ["super+."], "command": "auto_complete" }
]

duplicate_line.py

import sublime, sublime_plugin

class DuplicateLineCommand(sublime_plugin.TextCommand):
    def run(self, edit, force_lines=False):
        for region in self.view.sel():
            if force_lines or region.empty():
                line = self.view.line(region)
                line_contents = self.view.substr(line) + '\n'
                self.view.insert(edit, line.begin(), line_contents)
            else:
                self.view.insert(edit, region.begin(), self.view.substr(region))