An n-pass linter

[TotalVerb]

This is a big change that switches the current one-pass linter to a as-many-passes-as-needed linter. It should be a big step toward removing spurious symbol not found problems. Currently there are a lot of broken tests, but they should mostly not be too hard to fix.

This breaks a lot of backward compatibility for LintContext, LintMessage, etc., because large portions of the infrastructure had to be rewritten. I'll document the changes.

Closes #12.

[coveralls]

Coverage increased (+1.3%) to 92.114% when pulling a5d4807 on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.3%) to 92.084% when pulling 57c7de0 on fw/npass into 7f311ed on master.

[TotalVerb]

Running this on packages tends to yield a barrage of "local variable shadows global" problems (the new I340, I341, I342, I343). This is consistent with every package I try it on. They're not false positives but very annoying, so it might make sense to disable them by default.

[coveralls]

Coverage increased (+1.1%) to 91.909% when pulling 23a275a on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.1%) to 91.895% when pulling c7e9578 on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.1%) to 91.895% when pulling 1f2229e on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.06%) to 91.844% when pulling 1f2229e on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.06%) to 91.844% when pulling f96d0ad on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+1.8%) to 92.599% when pulling ada82a3 on fw/npass into 7f311ed on master.

[musm]

would it ever be the case where this is not defined ?

[TotalVerb]

On 0.5, Base.error_color doesn't exist, because errors and warnings are both printed in Base.warn_color().

[coveralls]

Coverage increased (+1.9%) to 92.71% when pulling 8c1d5a0 on fw/npass into 7f311ed on master.

[coveralls]

Coverage increased (+2.0%) to 92.869% when pulling 393b5cd on fw/npass into 60a2068 on master.

[coveralls]

Coverage increased (+2.0%) to 92.845% when pulling 5e5fea5 on fw/npass into 60a2068 on master.

[coveralls]

Coverage increased (+2.04%) to 92.929% when pulling 8d46ed5 on fw/npass into 60a2068 on master.

[coveralls]

Coverage increased (+2.04%) to 92.929% when pulling bf7e902 on fw/npass into 60a2068 on master.

[TotalVerb]

I think I'll merge this soon to give it time to simmer on master, in case people who are checkouting Lint are depending on the removed features. However this isn't ready for tagging yet; there are still a lot of broken tests that need to be fixed.