Make -DPROGRAM_NAME able to set `Lasercake --version` output
release-build: use cmake -DPROGRAM_NAME= on all platforms
update DEVELOPER_README release process description
set CMakeLists.txt version number to 0.22.1 release
release-build: Be more cautious about reusing Lasercake-source git dir

This only reuses the directory when pulling from the same origin
as before.

This also fixes a specific problem where `git pull https://...` didn't
pull tags at some times that `git pull` did.
Add a changelog
Add Travis CI configuration
Say "canny" and "careful", never "paranoid" which is ableist
"assert_if_ASSERT_EVERYTHING" -> "maybe_assert"

These assertions are for debugging
so they should be quick ish to type.

The "assert_everything" define and variable is
renamed to "canny" to match the CMake option.