feat: add until EOF

make it impossible to advance past the end of the stream

feat: ensure that it's not possible to read before the start of the file

feat: make it impossible to increment index after EOF

fix: don't allow passing EOF to increment position

feat: allow input buffer size to be customised, and use a larger default

feat: added +x to push-tag.sh

fix issue with any swallowing parse errors

updated StringUntil to only succeed if the delimiter is found, hittin…

…g EOF is a problem

fix bug of incorrect positions returned when retreating back over new…

…lines