fixed index.md intro
fixed intro, again
added Least_common_multiple RosettaCode task
added egcd() to 'integers'
added Scala interop support for None/Some()
fixed errors in 'for' loop parsing
fixed Dot_product RosettaCode task to use section syntax
started fixing up the grammar - made 'or'/'xor' production left recursive to start with
get version number from manifest
made rules left recursive where appropriate in grammar
bumped version to 0.13-SNAPSHOT