FEAT: preliminary PARSE implementation
FEAT: added `rs-next` internal function support for series.
FEAT: PARSE now wired into the runtime and operational.

Only block! parsing works atm.
FIX: wrong native ID for PARSE.
TESTS: added block-end tests to parse tests
FEAT: PARSE now supports any-string parsing.
FIX: corrupted `type` variable in many places.
FIX: input advancing is now mainly done when matching occurs, ST_NEXT_INPUT have been repurposed to do one step forward only.
FEAT: replaced /ALL by /OVER. /ALL is now the default mode. /OVER skips spaces.
FIX: minor code cleanups.
FIX: fixed rules overflow bugs, factorized exit code in new ST_END state. All tests passing now.
FIX: improved handling of words evaluation in PARSE. Fixes some use cases.
TESTS: reformatted some tests, plus additional string tests.
FIX: symbol base index off by one in dump-symbols debugging function.
FIX: COPY/PART wrongly process part argument if series.
FEAT: added internal `rs-abs-at` function for returning the element at and absolute index.
FIX: minor code factorization in string.reds.
FIX: missing fix for COPY/PART on string! series.
FEAT: added internal `none/rs-push` function.
FEAT: add support for COPY, SET, TO, THRU, NOT, QUOTE, INTO commands in PARSE.
FEAT: significantly improved the composability of PARSE rules by changing rules stack usage.
FIX: many bugs revealed by PARSE unit tests.
TESTS: additional PARSE tests.
FIX: minor indentation fixes (removing extra spaces).
FIX: avoid compiling debug function in non-debug mode.
FIX: minor comment fix.
FEAT: optimized speed of TO/THRU when having a literal value as argument.
FIX: wrong exit state for NONE.
FIX: minor code improvements.