added optional filter for list comprehensions
added lists module and fixed conversions to string
added lists.funl
fixed test-mergesort.funl and test-quicksort.funl
fixed 'lists'
added test.funl
added test.funl to resources temporarily for easier testing
fixed parser to work for empty source files
fixed function part selection
added RosettaCode Draw_clock task
added sys module
fixed failure to convert long to bigint when dereferencing
added rosettaCode tasks as separate runnable modules
the value of a 'for' loop is now always () even if there's an 'else' clause
fixed break and continue not restore execution environment correctly
fixed glitch in variable lookup create by the previous fix
unified code for 'for' loops and list comprehensions
unified grammar for 'for' loops and list comprehensions
make type and grammar changes to support multiple generators
added support for multiple generators in 'for' loops and list comprehensions