Use "SNR" instead of "SID" in maparg() comparison

While "<SID>" is used for maps, it will be replaced by "<SNR>.." and
that is what maparg() returns.
Add `g:endwise_no_mappings` to allow skipping maps

This allows to work around issues like issue #22
(https://github.com/tpope/vim-endwise/issues/22)
Fix remap issue
Add C and C++ PreProcessor support

I add #if, #ifdef, #ifndef support.
If you type <CR> at the line which starts with them, #endif would be
added.
Add xdefaults to preprocessor support
Fix detection of #endif
endwise.vim 1.1

* Add support for Lua, Bourne shell, and C preprocessor.
* Detect delimitMate mapping and append accordingly.
* Add `g:endwise_no_mappings` to allow skipping maps.
Use shorter versions of end{whatever} in VimL

Instead of:

```vim
if {whatever}
endif

fun! {whatever}
endfun
```

This alters the vim-filetype settings to produce:

```vim
if {whatever}
end

fun! {whatever}
endf
```

These are not the absolute shortest commands (see below), just the ones
I prefer.

:en[dif]
:endfo[r]
:endf[unction]
:endt[ry]
:endw[hile]