really fixes #12 I was too fast at committing the previous diff. The previous commit will effectively ignore "ignored" files, but also up-to-date ones! This de-ignore (is that a word?) the up-to-date files, while still hiding the ignored ones. Hope this makes sense.

closes #12 The rationale is that `got status` doesn't print the status of the file if it is either up-to-date or ignored by .gitignore or .cvsignore. Thus, we were marking as up-to-date the ignored files in *vc-dir*. (vc-got-state was working as expected.) This tries to fix the situation. File for which `got status` doesn't print any info are saved in a double-check list, and we issue a second `got status` only against the double check list, and push onto res only the up-to-date ones.

I got tired of `n` a millions of time when debugging vc-got-dir-status-files, so I extracted it to its own function. (yeah, I could have used a conditional breakpoint, but I feel this is more readable)

added some process-file-side-effect around, minor style fixes, some minor docs improvements. No (theoretically) functional changes.

this somewhat breaks (?) the contract of the function, but this doesn't seem to have bad effects.

This way we can control how each file gets displayed in the *vc-dir* buffer and display the staged information. The advice around vc-dir-move-to-goal-column is needed otherwise `n' and `p' moves the cursor to the wrong column. vc-dir.el hardcodes that value to 25.

after the last change to vc-got--status it wouldn't return 'up-to-date.

Changed how vc-got--status works: before it returned a string representing the output of "got status", now a data structure. Elisp is better (and more efficient) at managing buffers instead. Additionally, now it parses also the stage information and has a flag to list only file with certain status flag (i.e. only conflicted files, only added files, ...)