Merge pull request #5 from rmmh/gh-pages

don't spellcheck programs
adding support for the reverse subtract op.
we need more power, cap'n
better rangechecks for arguments and literals.
carry flag for subtraction was backwards. whoopsie.
formatting and cleanup on the programming guide.
checking in a slightly cleaned-up version of an old game originally written in an older version of Octo.
an experiment in raycasting. Also the reason the Octo IDE offers hyperspeed settings.
checking in an old prototype.
a slightly better way to handle default entries in a jump table.
added a little logic so that octo will halt immediately when it encounters an interpreter error instead of running off into infinity, screaming nonstop
added code to allow the typing of tab characters in the editor.
tagged tokens with their indices in the program, allowing the compiler to highlight errors when they are encountered.
made pixel's number parsing code more robust and permissive. Any data which is accepted by Octo as a sprite should be pasteable now.
fixed an off-by-one error for calculating token boundaries at the end of the editor.
if something fails to compile, don't blindly run the last working version anyway.
added some basic error checking for mismatched control structures.
added support for register aliases with :alias
reintroduced :const
updated documentation to reflect new features