clean up old screenshots in start.pl not in isotovideo
add a 3rd thread handling outside commands

redefine QEMUPORT to be the port of qemu (got lost somewhen :)
QEMUPORT+1 has a HTTP server running mojolicious::lite
implement routes used by tests:

/data for a cpio archive of the distri's data directory
/data/#filename for a single file from data
/uploadlog/#filename for uploading a log file
a bit cleanup in the documentation
Merge pull request #123 from os-autoinst/http_server

Http server