basic impl of fs.stat
call next test after running stat test
update mtime on truncate/ftruncate; ensure each stat happens after last one
factor out updating mtime
don't truncate to same size
implement Connection.lastModifiedImpl
correct status of Connection.truncate tests
update number of passing fs.js unit tests
Merge branch 'master' into lastModifiedImpl

Conflicts:
	tests/automation.js
flatten stat/mtime tests
add ftruncate tests; always set lastTime to prevent failures busting subsequent tests
reuse lastTime and modifiedTime vars for simplicity
test truncate to larger size
Merge branch 'master' into lastModifiedImpl
expand comment
stop converting from millis to micros then back
make lastModified return 0 if file doesn't exist
explain modification to Connection.lastModified()
Fix Math.fround polyfill
Re-enable commented out tests in TestArithmetic. Fixes #270.