BUGFIX: Matlab completion now works with structs

[brunobeltran]

This patch should fix #52.

The problem was that the MetaKernel framework expects do_matlab_complete('some_struct.long') to return 'some_struct.long_fieldname', but mtFindAllTabCompletions returns 'long_fieldname' instead.

This was fixed by asking do_matlab_complete.m to manually re-add the prefix. Matlab's isstruct function is used to make sure that the prefix that's being added back is actually a struct, instead of trying to use regular expressions to find the prefix, since that prevents corner cases where filenames that are valid Matlab identifiers are confused for structs that don't exist.

In practice, this means autocompletion will work correctly on test.p[TAB] whether test.py is a script in the current directory, a field py of the struct test, or both.

Also corrected some tab/spaces inconsistencies in the relevant files, and did some more name mangling to make sure that evalin(base, ... doesn't cause any problems if the user has a variable named e.g. completions_output.

[blink1073]

Thanks!

[Foucl]

thank you so much! (even though I know feel guilty for making you feel guilty ;-))