Extend support for fifosignal/fifowait.

Now pressing F12 will signal the fifo in the the directory of the
current file instead of $PWD.  This way, it's easier to have multiple
fifos working together in a single Vim session.

Also, reference implementations of fifosignal and fifowait are now
embedded in vimfiles.
Catch E42 as another "no next/prev message" exception.

Also, on success echo an empty line to clear any previously written
message.
colors/szakdark: fix WildMenu and Pmenu colors

WildMenu was a bit too wild, so it's been toned down.  Added cterm
equivalents for Pmenu and PmenuSel.
Move encoding-related settings to early-setup phase.
Make timeout settings explicit.
Upgrade CtrlP plugin to 2013-07-29 to pick up patch "Leave 'mouse' as-is"; without this patch, when TERM=konsole and CtrlP is invoked, libgpm hangs.
Remove termsupport.vim, termtest.vim in preparation for vim-fixkey.
Add vim-fixkey to fix key codes for console Vim.
Merge branch 'fix-menu-colors' of https://github.com/jszakmeister/vimfiles
Update vim-fixkey to version 0.2.1.