Capture full RC number, not just a single digit

Previously the + fell outside the capture, which meant that multi-digit rc
numbers would break. This commit moves the + into the capture, so the full RC
number can be retrieved. It also includes an updated test that fails without
this fix, but passes with the fix.
Merge pull request #150 from haus/rc_num_fix

Capture full RC number, not just a single digit