Add NetTiles, a new Tiles interface with online play support (v24)

Add NetTiles, a new Tiles interface with online play support (v24)

Changes in v24:
- misc fixes

Changes in v23:
- fix monster stab/etc. brands for the non-list case
- fix reference-after-free and bad sizing logic
- fix x/y typo leading to wrong player position
- fix statues

Changes in v22:
- fix silly bug (thanks to pointless)

Changes in v21:
- rewrite viweport sizing calculation, name label positions should be fixed
- fix windows build

Changes in v20:
- all resolution problems should now be fixed
- now console viewport is no longer 1:1 with tiles viewport
- text and menus on low resolution now works (terminal size is >= 80x24)
- low resolution players can now watch anything
- note that >= 1600x1000 is still needed to see as much as you would with
  console version defaults, but NetTiles will adapt correctly by
  cutting and centering the viewport on lower resolutions

Changes in v19:
- redone input system, although the result is essentially the same
  as the old one

Changes in v18:
- report connection errors properly
- fix ssh compression, was probably broken and not being used

Changes in v17 (thanks to pointless, edited by me):
- fix malloc.h
- fix WSA startup

Changes in v16:
- add util/test-libssh.c to git

Changes in v15:
- link to winsock on mingw

Changes in v14:
- really fix windows more

Changes in v13:
- fix windows build more

Changes in v12:
- fix windows build

Changes in v11:
- fix orcish idols
- fix mingw build

Changes in v10:
- no longer adds a main menu that displays before the normal one
- adds "Play Online" to the existing main menu
- online play menu rewritten to use new PrecisionMenu
- adds support for all resolutions (even 640x400), except for watching

Changes in v9:
- fix water regression
- improve detect items

Changes in v8:
- fix tiles shaded as "detected" incorrectly

Changes in v7:
- fix missing plant/mushroom tiles
- fix out of range rays
- fix some monsters being ambiguous inappropriately

Changes in v6:
- add 0.6 skeletal dragon

Changes in v5:
- add support for Fn keys
- fix monster glyph support

Changes in v4:
- fixed compilation
- fixed manes
- fixed abominations and orb guardians appearing as explosion tiles
- fixed cursor/beam path showing incorrectly
- misc fixes and refactorings

Changes in v3:
- now recognizes special monsters in wizlabs and vaults

Changes in v2:
- rebased over Crawl master
- rebase gives new awesome zombie/skeleton/spectral tiles
- unseen monsters shows as detected instead of guessed with "???" tag
- item heap icons implemented
- character mode now support reverse
- beam path shown shaded like in Tiles
- viewport/message separation hopefully better detected
- better player detection (now works when targeting)
- libssh now optional, telnet used otherwise

Includes a partial copy of PuTTY, under a BSD-like license, for
terminal emulation.

Can optionally use an external libssh for SSH support, and will
use Telnet exclusively otherwise.

Use make NETTILES=1 to build.

Note that you probably need a 1600x1000 or higher resolution for this
to be usable, since the viewport is not stripped: hopefully this will
later be fixed.

refactor parsing logic and fix 0.6 manes/demonic crawler