Addresses #4771

Starting with Emacs 24.4 the meanings of Enter and Ctrl+J was swapped, so that
RET does newline-and-indent while C-j is the simple non-electric newline.  This
change makes codemirror4 match Emacs.

https://vi.stackexchange.com/questions/6061

Closes #4552

The current situation prevents to remove bindings from the default keymap in vim
mode. It is sometimes required to be able to delete them in order to do some
custom mapping.

Example:

1. The `h` binding is defined in the default keymap for moving left.

2. The user want to set the custom binding `h<character>` to behave like
   `r<character>`. It can do so with:

     CodeMirror.Vim.mapCommand('h<character>', 'action', 'replace', {},
                               { isEdit: true, context: 'normal' });

3. When the user press the `h` key, the code searches for all the keybindings
   matching it [1].

4. Two bindings are found:

   - The default binding `h` for moving left. This is a FULL match.
   - The user-defined `h<character>`. This is only a PARTIAL match as it is
     expecting another character.

5. The code is preferring FULL matches over PARTIAL matches whenever they are in
   competition [2]. The code then selects the move left action.

6. The way to let the user-defined binding take over is to let the user delete
   the default binding:

     CodeMirror.Vim.unmap('h');

   but this is not possible because it is not allowed to delete bindings from
   the default keymap [3].

This commit remove such differentiation by treating all bindings in the same
way, letting the responsibility to the user to not mess with the bindings he
needs.

[1] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L1098
[2] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L1099-L1103
[3] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L4182



Signed-off-by: Fabien Dubosson <fabien.dubosson@gmail.com>

Selecting two full lines including line ends makes a selection from
line 1 to line 3 (ch: 0). This command used to sort three lines (1 to
3) which is not what I expect. This change makes it sort only two
lines if there are no selected characters on the last line.

It also fixes a fatal error if there are more than one selection on
the same line (the code used 'range' instead of 'ranges').

It also selects the trailing newline after sorting the lines so that
the whole lines are selected.

so other potential emacs-type modules can use

Closes #4419

In Replace mode (or Overwrite mode) it should still go backwards
without deleting characters.

and remove autocomplete bindings

This reverts commit 8dbb84f4.

Issue #3127

Issue #3991

The Error after the while(true) loop is not reachable and should
be removed. The "this.iterator" property should be given an
initial value of 0. This fixes two warnings reported by Closure
Compiler.

cm.save() might not exist if CodeMirror is not created from a
textarea. This adds an additional check to prevent TypeErrors.