add get-info function to Pollen reader for better compatibility with DrRacket
make exports visible as top-level identifiers in REPL
delete obsolete comment
add #lang tests
update references to sugar module
update other sugar references
update use of 'get'
update remove-all-ext to remove-ext*; move file-extension tests to sugar module
remove use of 'try'
update 'trim' to 'trimf'
change splitf-at* to filter-split
progress
Merge branch 'master' into dev-tutorial
progress