FIX: wrong jumping pointer calculation for POKE action in `actions/poke`.
FIX: avoid FIND and SELECT actions change input series index.
FIX: stack adjustments for FIND action.
FEAT: preliminary support for path! and set-path! evaluation from the interpreter.

Currently supported datatypes in paths (by interpreter): word!, get-word!, integer!.
FIX: temporary fix for #416
FIX: issue #417 (Can't load multi-line string with REBOL header)
FIX: final fix for issue #416 (Interpreter corrupts argument passing on path access)
FIX: issue #415 (Compile crash on nested functions)
FEAT: moved inner code for interpreter's path evaluation into a sub-function.
FIX: additional fix for issue #416.
FEAT: lit-path! evaluation added to the interpreter.
FEAT: added paren! evaluation support in both path! and set-path! for interpreter.
FIX: now include files tracking lists are cleaned up when compilation is done.
FEAT: minor code cosmetic clean-ups.
FEAT: added paren! support in paths for compiler.
FEAT: added REDUCE native in compiler. /into option implemented.

/into will append the reduced values to the argument block instead of inserting them. The reason is that INSERT action has not yet been implemented.
FEAT: added REDUCE native support to interpreter.
FEAT: more general-purpose `eval-next` function.
FEAT: now REDUCE supports non-literal block argument (both in compiler and interpreter).
TESTS: initiated the interpreter tests.
FIX: wrong code generated by compiler for empty block! series passed to REDUCE.