Adding implicit semi-colon parser to Nemerle

Similarly to Scala, I thought it would be nice if Nemerle had an option
to use implicit semi-colon type syntax, where semicolons are optional.

To that end, I've added this feature to the trunk. It includes tests,
examples, etc.

Usage is either:
1) Add the "-isc" switch when building using ncc
2) Use "pragma implicit" (similarly to "pragma indent" as the first line
in a code file.