Make `python-shell-completion--do-completion-at-point' work for calls done via `python-completion-complete-at-point'.

The comint prompt retrieval logic was failing on
`python-shell-completion--do-completion-at-point' when calls to it
happened from outside the process buffer.
Make `python-shell-completion--do-completion-at-point' to return a list for `completion-at-point' do it's job instead of replicating completion logic.

Removed vars:
 + python-shell-completion-original-window-configuration
Enhanced completion subject finding logic for `python-shell-completion--do-completion-at-point'
Added missing dot in `python-completion-complete-at-point' error
Enhancements on ipython 0.10 setup documentation (thanks to @tkf for the hint)
Pass entire line of input to module completer

The module completer wants e.g. 'from xxx' as input, not just 'xxx'.

This change also causes all modules to be offered as completions to
'from ', whereas previously this was regarded as empty input.
Use `completion-at-point` instead of `comint-dynamic-complete` in shell completion
Merge pull request #71 from dandavison/fix_module_completion

Pass entire line of input to module completer
Deactivate mark on python-shell-send-region
Disregard leading whitespace when forming module completions

This allows an indented import line (e.g. in a function or method
body) to be completed.
Don't send "if __name__ == '__main__':" to interpreter
Customizable variable to control syntax highlighting in shell.

Default is on.
Merge pull request #78 from dandavison/no-eval-if-name-main

Don't send "if __name__ == '__main__':" to interpreter
Small fix in `python-shell-send-defun' (#69 thanks mafm-git!)
Merge branch 'master' of github.com:fgallina/python.el
Merge pull request #77 from dandavison/drop-leading-whitespace-in-module-completion

Disregard leading whitespace when forming module completions
Treat empty triple quote

Fix #70
Merge pull request #83 from tkf/empty-triple-quote

Handle empty triple quotes correctly
Merge pull request #76 from dandavison/deactivate-mark-on-send-region

Deactivate mark on python-shell-send-region
Merge pull request #72 from dandavison/change_completion_service

Use `completion-at-point` instead of `comint-dynamic-complete`