Some improvements for helping new contributors get started with the more advanced
hacking aspects of the randomizer, and simplifying re-setting up an environment
on new hardware/installs for existing contributors.

README.md & others: Consistently use Project64's canonical name in documentation.

ASM/README.md: Add headers, more detailed instructions on installing the toolchain,
including methods described in Discord #dev-resources channels. Also mention a
potential issue with trying to use the Project64 symbols on a default install.

ASM/build.py: Add additional subdirectories of `tools` to PATH. Makes above
instructions simpler.

ASM/.gitignore: Ignore everything in the `tools` directory (except .gitkeep as with roms)

Windows: armips requires the VC++ redist installed
but doesn't currently provide it. MSYS2 is required
for the files prepackaged on dropbox.

The rest is mostly stuff people on the affected
platforms should be used to so detail is not added.

Mention the compilers required on other platforms for armips as well.

Typo and reword previous commit.