Save entire command history - Updated, Fast

Inspired by http://www.mathworks.com/matlabcentral/fileexchange/9291-save-entire-command-history.
`preserve_history.m` maintains a complete record of the command history (MATLAB only maintains the last 20k worth of commands, so old commands are lost).
This package is much faster than the above original (uses regexp to match all content instead of line by line) and is compatible with Matlab R2014a and R2014b which save history in XML format. There is also no need to edit/copy any files, the entire process is automatic. You also don't need to copy the files to $MATLAB/toolbox/local/, which usually requires admin permissions.

To install, just extract the attached files to `%USERPROFILE%\Documents\MATLAB` (on Windows) or `~/Documents/MATLAB` (Linux, MacOSX), which should already be in your Matlab path by default.

The preserved history file is called `history_preserved.m` and will be placed in `%APPDATA%\Mathworks\MATLAB\R2014a` (Windows) or `~/.matlab/R2014a` (Linux, MacOSX).

If all goes ok, quitting/exiting Matlab will trigger `preserve_history.m` automatically. You can also manually execute `preserve_history.m`.

Tested in Windows, Linux and MacOSX.