Dont force ../.deps in third-party/CMakeLists.txt

- third-party is built under .deps by default instead of using its own
  ${CMAKE_BINARY_DIR}, move this default setting out of the cmake
  settings and into the Makefile.
- As a consequence the workflow of building third-party using CMake
  should feel more natural, avoid the additional folder or setting
  DEPS_DIR from the command line.
- This commit does not change the default behaviour when calling the
  Makefile wrapper.
Allow cmake caller to override DEPS_PREFIX

- Caller can override bundled dependency location using
  DEPS_PREFIX
- Cache variable DEPS_PREFIX, using .deps/usr by default
- Removed unused variables DEPS_BIN_DIR, DEPS_BUILD_DIR, DEPS_DIR
  DEPS_INSTALL_DIR
- Corner case: if the caller tries to override DEPS_PREFIX after a
  successful cmake configuration, the caller needs to clear the cache
  because dependency checks are based on the old value
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.
Merge pull request #1588 from equalsraf/tb-no-central-deps

Dont force ../.deps in third-party/CMakeLists.txt use the Makefile instead
vim-patch:7.4.423

Problem:    expand("$shell") does not work as documented.
Solution:   Do not escape the $ when expanding environment variables.

https://code.google.com/p/vim/source/detail?r=v7-4-423
Update busted to 2.0.rc4.
Merge pull request #1702 from fwalch/update-busted

Update busted to 2.0.rc4.
Merge pull request #1701 from fwalch/vim-7.4.423

vim-patch:7.4.423
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