Don't double-encode URLs before parsing them

<https://code.google.com/p/macvim/issues/detail?id=316> wasn't a bug.

When you're constructing a URL, you *should* end up escaping URL-unsafe
characters twice: once for the `file:` URL and once for the `mvim:` URL.
Escaping it inside MacVim breaks legit URLs with escapes at the `mvim:` level.
updated for version 7.4.017
Problem:    ":help !!" does not find the "!!" tag in the help file. (Ben
	    Fritz)
Solution:   When reading the start of the tags file do parse lines that are
	    not header lines.
Added tag v7-4-017 for changeset c47c8cd5fe5c
updated for version 7.4.018
Problem:    When completing item becomes unselected. (Shougo Matsu)
Solution:   Revert patch 7.3.1269.
Added tag v7-4-018 for changeset 460d5be9395e
updated for version 7.4.019
Problem:    MS-Windows: File name completion doesn't work properly with
	    Chinese characters. (Yue Wu)
Solution:   Take care of multi-byte characters when looking for the start of
	    the file name. (Ken Takata)
Added tag v7-4-019 for changeset d5eb32dc231c
updated for version 7.4.020
Problem:    NFA engine matches too much with \@>. (John McGowan)
Solution:   When a whole pattern match is found stop searching.
Added tag v7-4-020 for changeset c1ae5baa41f4
Use “inoremap” for <M-BS> and <D-BS>

As a Mac user I’m used to using Option-Delete to delete to the beginning of the previous word; MacVim sets up this behavior with its gvimrc. But I also like to use Control-W to delete to the beginning of the line. This change makes it possible for these two mappings to coexist without a problem.
Use “noremap” for all other mappings too
updated for version 7.4.021
Problem:    NFA regexp: Using \ze in one branch which doesn't match may cause
	    end of another branch to be wrong. (William Fugh)
Solution:   Set end position if it wasn't set yet.
Added tag v7-4-021 for changeset c514693882b9
updated for version 7.4.022
Problem:    Deadlock while exiting, because of allocating memory.
Solution:   Do not use gettext() in deathtrap(). (James McCoy)
Added tag v7-4-022 for changeset 965044860b7f
Merge pull request #34 from bdesham/patch-1

Use “noremap” in system gvimrc
Merge pull request #33 from Sidnicious/patch-1

Don't double-encode URLs before parsing them
Merge branch 'vim'
Snapshot 71
* Better icons