Fix metadata removal on upload for files with un-sane characters in them

When re-uploading a file with characters that will be later sanitized,
the old metadata entry wasn't removed because it checked the unsane
filename rather than the sanitized version that will later be stored.

This was creating an inconsistent metadata view during analysis for
files with spaces in them.
Update job metadata when the gcodemanager signals a change
Remove superfluous selectedFile setting as setJobData does that
Added a note to please create pull requests against devel
Added left space on filesystem holding the uploads folder to the gcode files list

Closes #186
Merge branch 'master' into devel
Just in case we'll use subfolders in the future...
Merge branch 'CapnBry-job-metaupdate' into devel