Moved subr-compat.el, dflet.el to wg-compat.el

Also a lot of function aliases were removed.
Todo: replace them with cl-...

Save variables without a serialize function

If the only thing to do is to save some local variable you can use

(save . (var1 var2 ...))

instead of a serialize function

Removed the hard-coded name for inferior sml buffers

We now get the buffer name using

(concat "*" (file-name-nondirectory inf-sml-program) "*")

Restoring compilation buffer

Actually restoring just it's name so that the next process is run in
this buffer.

fix for #15

Checking arguments for positioning of the frame.
Sometimes it's not just an integer.

desktop-save-mode fix

Was caused by keyboard-quit function

new variables + fixes

* wg-restore-frame-position t
* wg-remember-frame-for-each-wg nil
* wg-incorrectly-restored-bufs nil
A list of incorrectly restored buffers
* wg-record-incorrectly-restored-bufs nil

new variable wg-mode-line-disable + powerline fix

wg-mode-line-disable is by default (featurep 'powerline)

reorganized description, changed link

- changed link to special buffers help page

restoring prolog interpreter + fixes

- switching to Python shell now works
- checking directory existence for Magit
- restore prolog shell

basic support for python shell buffer

Restoring inferior-python-mode buffer in a directory
it was started

easy install + autocreate first workgroup

- installation - just activate WG
- changed some default variables (prefix key, session file, morph)
- automatically create first workgroup

make settings a bit easier

- use ~/.emacs_workgroups as a default wg-file
- wg-restore-associated-buffers is nil by default
- desktop-save-mode removed