put path/to/file s3://... should leave off the relative path on the destination file

[barnybug]

This behaves more like 'cp' intuitively. s3 put local/file s3://.../path uploads to s3://.../path s3 put local/file s3://.../path/ uploads to s3://.../path/file s3 put local s3://.../ uploads s3://.../local/... s3 put local/ s3://.../ uploads s3://.../l... s3 put local1/file1 local2/file2 s3://.../path - should refuse s3 put local1/file1 local2/file2 s3://.../path/ - uploads to s3://...path/file[12] s3 put local1/file1 local2/file2 localpath - should refuse