Rebind Home and End to StartOfLine and EndOfLine

This commit changes the default keybindings for Home and End. It
also changes the InsertEnter action to InsertNewline (a better name)
although InsertEnter is still valid for backwards compatibility.

Closes #206

runtime/help/help.md

@@ -43,13 +43,14 @@ you can rebind them to your liking.
 	"CtrlDown":       "CursorEnd",
 	"CtrlShiftUp":    "SelectToStart",
 	"CtrlShiftDown":  "SelectToEnd",
-	"Enter":          "InsertEnter",
+	"Enter":          "InsertNewline",
 	"Space":          "InsertSpace",
 	"Backspace":      "Backspace",
 	"Backspace2":     "Backspace",
 	"Alt-Backspace":  "DeleteWordLeft",
 	"Alt-Backspace2": "DeleteWordLeft",
-	"Tab":            "InsertTab",
+	"Tab":            "IndentSelection,InsertTab",
+	"Backtab":        "OutdentSelection",
 	"CtrlO":          "OpenFile",
 	"CtrlS":          "Save",
 	"CtrlF":          "Find",
@@ -63,11 +64,11 @@ you can rebind them to your liking.
 	"CtrlD":          "DuplicateLine",
 	"CtrlV":          "Paste",
 	"CtrlA":          "SelectAll",
-	"CtrlT":          "AddTab"
+	"CtrlT":          "AddTab",
 	"CtrlRightSq":    "PreviousTab",
 	"CtrlBackslash":  "NextTab",
-	"Home":           "Start",
-	"End":            "End",
+	"Home":           "StartOfLine",
+	"End":            "EndOfLine",
 	"PageUp":         "CursorPageUp",
 	"PageDown":       "CursorPageDown",
 	"CtrlG":          "ToggleHelp",
@@ -79,14 +80,14 @@ you can rebind them to your liking.
 	"CtrlQ":          "Quit",
 	"CtrlE":          "CommandMode",
 	"CtrlW":          "NextSplit",
-	
+
 	// Emacs-style keybindings
 	"Alt-f": "WordRight",
 	"Alt-b": "WordLeft",
 	"Alt-a": "StartOfLine",
 	"Alt-e": "EndOfLine",
 	"Alt-p": "CursorUp",
-	"Alt-n": "CursorDown"
+	"Alt-n": "CursorDown",
 }
 ```