Some parts of the code were using case-insensitive
matches when searching for an identifier (i.e.
TODO and todo would both be acceptable) whereas
other parts of the code would search for a strict
case-sensitive match (only TODO, not todo). This
inconsistency led to many issues, among them
- #216
- #224
- #225
Further, the identifier match wasn't being done
using word breaks, meaning an identifier of "FIX"
would match (case-insensitively) with "suffix" or
"prefix" if those words happened to appear in a
comment. (See #234).
Issue #230 was also preventing issue labels from
being applied properly if the identifier case
did not match exactly the canonical version. i.e.
"todo" would generate an issue, but the associated
labels wouldn't be applied because the exact
identifier used wasn't "TODO".
This commit resolves all of these issues.
Split main.py into modules to (mostly) isolate the
GitHub-specific code from the general TODO
detection and program logic.
This is both for readability/maintainability and
to prepare for potentially supporting other
version control systems (e.g. GitLab, BitBucket).
