Minor evaluation fixes

See merge request bob/bob.ip.binseg!11

[script/binseg] In evalpred, allow user to specify the prediction map extension, but defaults to .png

Cast vector types to avoid issues with pytorch > 1.0

See merge request bob/bob.ip.binseg!10

Minor fixes

See merge request bob/bob.ip.binseg!9

[conda] Remove "license_file" keyword from recipe (addresses bob/bob.devtools#44, see bob/bob.devtools!127)