Use a local viminfo file when running the old tests.

This is required after defaulting to `nocp`, so that ~/.nviminfo
files don't interfere with the old legacy tests.
Remove superfluous settings from legacy tests.
Reimplement :drop (vim-patch:0)

The :drop ex command was inadvertently removed when removing FEAT_GUI.
This patch reintroduces it.
Define and use the ARRAY_SIZE macro

A similar macro is defined in the Linux kernel [1].

To refactor the code I used a slightly modified Coccinelle script I found in
[2].

```diff
// Use the macro ARRAY_SIZE when possible
//
// Confidence: High
// Copyright: (C) Gilles Muller, Julia Lawall, EMN, DIKU.  GPLv2.
// URL: http://www.emn.fr/x-info/coccinelle/rules/array.html
// Options: -I ... -all_includes can give more complete results

@@
type T;
T[] E;
@@

- (sizeof(E)/sizeof(*E))
+ ARRAY_SIZE(E)

@@
type T;
T[] E;
@@

- (sizeof(E)/sizeof(E[...]))
+ ARRAY_SIZE(E)

@@
type T;
T[] E;
@@

- (sizeof(E)/sizeof(T))
+ ARRAY_SIZE(E)

@n@
identifier AS,E;
@@

- #define AS(E) ARRAY_SIZE(E)

@@
expression E;
identifier n.AS;
@@

- AS(E)
+ ARRAY_SIZE(E)
```

`spatch --in-place --sp-file array_size.cocci -I src/ -I build/include/ -I build/src/nvim/auto/ src/nvim/*.c`

[1] http://lxr.free-electrons.com/source/include/linux/kernel.h#L54
[2] http://www.emn.fr/z-info/coccinelle/rules/#macros
Use ARRAY_SIZE where Coccinelle wasn't able to do it
Change the signature of intable() (mbyte.c) to use ARRAY_SIZE
Change the signature of utf_convert() (mbyte.c) to use ARRAY_SIZE
vim-patch:7.4.434

Problem:    gettabvar() is not consistent with getwinvar() and getbufvar().
Solution:   Return a dict with all variables when the varname is empty.
	    (Yasuhiro Matsumoto)

https://code.google.com/p/vim/source/detail?r=v7-4-434
vim-patch:7.4.442

Problem:    Using unitinialized variable.
Solution:   Pass the first window of the tabpage.

https://code.google.com/p/vim/source/detail?r=v7-4-442
Merge pull request #1699 from three-comrades/fix-viminfo

Use a local viminfo file when running the old tests.
Merge pull request #1638 from Grimy/ex-drop

Reimplement :drop
Merge pull request #1704 from fwalch/vim-7.4.434

vim-patch:7.4.434, vim-patch:7.4.442
Merge pull request #1663 from philix/array_size

Define and use the ARRAY_SIZE macro
vim-patch: Mark patches as NA.
Merge pull request #1707 from fwalch/na-patches

vim-patch: Mark patches as NA.
Remove VMS remnants
Remove dec-mcs remnants

It was (apparently) the default character encoding file used for line
printing on VMS, which is unsupported.
Remove Amiga remnants

Notes regarding the removal of specific items:

  - Aztec C: only on the Amiga.
  - mch_check_win(): doesn't exist anymore.
  - Comment in ex_cmds.c: It seems the context for this comment was
    removed, but the comment was inadvertantly left alone.