Add osh2oil errors to the FAILED.html output of test/wild.sh

Add TODO in osh2oil.py.  Parts of the language have changed.

test/wild.sh

@@ -117,18 +117,30 @@ _parse-and-copy-one() {
EOF

    log "*** Failed to parse $rel_path"
    return 1
    return 1  # no point in continuing
  fi
  #rm ${output}__err.txt

  if ! _osh-html-one $input $output; then  # Convert to HTML AST
    log "*** Failed to convert $input to AST"
    return 1
    return 1  # no point in continuing
  fi

  if ! _osh-to-oil-one $input $output; then  # Convert to Oil
    # Append
    cat >>$dest_base/FAILED.html <<EOF
    <a href="$rel_path.txt">$rel_path.txt</a>
    <a href="${rel_path}__osh-to-oil-err.txt">${rel_path}__osh-to-oil-err.txt</a>
    <a href="$rel_path.oil.txt">$rel_path.oil.txt</a>
    <br/>
    <pre>
    $(cat ${output}__osh-to-oil-err.txt)
    </pre>
    <hr/>
EOF

    log "*** Failed to convert $input to Oil"
    return 1
    return 1  # failed
  fi
}

tools/osh2oil.py

@@ -1,6 +1,8 @@
from __future__ import print_function
"""
fix.py -- Do source transformations.  Somewhat like 'go fix'.

TODO: Change := to =, and var/const/set
"""

import sys