filechecker.py - Fix - Manual Processing and Recheck Files

Two purposed changes to fix Manual Processing and Recheck Files. 

ln 128 & 132
Fixes issue with file names such as All-New_X-Men_2013_001.cbz. This causes subname to be '2013 001 cbr' which causes it to be registered as a decimal

ln 135
If the Year comes before the Issue # the subname is passed with no Issue number. This logic checks for numbers before the extension in the format of 1 01 001 and adds to the subname. (Cases where comic name is $Series_$Year_$Issue)