Add autosource plugin

Adds commands to source a vimscript on write. Useful when writing
errorformats.
Use noremap in python maps

Where applicable, use noremap instead of map to prevent maps from
breaking due to remaps.

Also use xmap instead of vmap since I don't need (and don't think I
want) selection.

Also fix file modes (chmod).
Remove special case: Unix and Windows are the same

A while back I made Unix and Windows have the same path (~/.vim), so I
don't need a special case for python tags.
Vimscript should be rw not executable

Fix chmod of some scripts.
Remove ft: multiple syntax is now supported

Looks like Vim 7.3 now highlights with multiple syntax files for python
embedded in vimscript, so I don't need to force this file to be python
syntax.
Move python ftplugins into python folder
Simplify loading of system plugins

Some tools offer vim integration and provide their own vimscript.
Instead of copying it to ~/.vim, use david#load_system_vimscript to
source it. The function returns whether sourcing was successful.

This function should be guarded with loaded_NAME so the plugins can be
disabled in local.vim (when that package is not and will not be
installed).

The function's return value is a good value for the loaded_NAME guard
(so it is defined but zero when we failed to load).

Use this function to load some python integration and add the plugins to
local_templates.
Update location of ipy.vim file
Update ipy to directly source the ipython script

The ipython script has been extensively updated. Source it directly
instead (so it always matches my version of ipython).

Unfortunately, the script is zipped, so I need to locally unzip it. Not
sure if this is worse than having a copy in my vimfiles.
Fix ipython maps - noremap, buffer, style

Should use noremap where possible. Some cases want the remap.

Use <buffer> to only apply the maps to python buffers.

Disable some undesirable maps (or ones I already do another way).

Change some map keys to my desired setup. I don't want C-s mapped.

I can't use <SID> functions.
Add uncommenting support for python

I could use a real commenting plugin... but this is good enough (we'll
see if I ever use it).
Add compiler for running python code

Allows you to walk the stack from errors.

Use the new compiler instead of setting makeprg/efm manually.
Move py_compile code into a compiler

Not sure if this is much simpler, but the errorformat is much better.
sub: Update vimscript snippets